Virtual Journal of Nanoscale Science & Technology

A subtilisin-like protein from soybean contains an embedded, cryptic signal that activates defense-related genes

Gregory Pearce, Yube Yamaguchi, Guido Barona, and Clarence A. Ryan
Among the arsenal of plant-derived compounds activated upon attack by herbivores and pathogens are small peptides that initiate and amplify defense responses. However, only a handful of plant signaling peptides have been reported. Here, we have isolated a 12-aa peptide from soybean (Glycine max) le ... [Proc. Natl. Acad. Sci. U.S.A. 107, 14921 (2010)] published Wed Aug 18, 2010.

Mesoporous PdCo sponge-like nanostructure synthesized by electrodeposition and dealloying for oxygen reduction reaction

Satoshi Tominaka, Tomoya Hayashi, Yusuke Nakamura, and Tetsuya Osaka
A mesoporous PdCo sponge-like nanostructure was successfully synthesized by the combination of electrodeposition and dealloying, and was evaluated as a catalyst for the oxygen reduction reaction of fuel cells. The synthesized film had a sponge-like mesoporosity consisting of 530 nm thick ligaments w ... [J. Mater. Chem. 20, 7175 (2010)] published Wed Aug 18, 2010.

Functional surface modification of natural cellulose substances for colorimetric detection and adsorption of Hg in aqueous media

Xuehai Zhang and Jianguo Huang
Immobilization of ruthenium dye or mercaptosilane monolayer onto metal oxide ultrathin film pre-coated cellulose nanofibres of natural cellulose substances yielded colorimetric sensing materials with high sensitivity and selectivity as well as good reversibility, and trapping materials with high eff ... [Chem. Commun. 46, 6042 (2010)] published Wed Aug 18, 2010.

Above-room-temperature ferroelectricity in a single-component molecular crystal

Sachio Horiuchi, Yusuke Tokunaga, Gianluca Giovannetti, Silvia Picozzi, Hirotake Itoh et al.
Abstract not available. [Nature 466, 1006 (2010)] published Thu Aug 19, 2010.

Synthesis, properties and uses of bacterial storage lipid granules as naturally occurring nanoparticles

Nicholas Thomson, David Summers, and Easan Sivaniah
Bacterial storage lipids including poly(hydroxyalkanoates), triacylglycerols and wax esters are biodegradable materials with applications in food production, household goods, cosmetics, packaging and medicine. They are produced as a carbon and energy store by a wide range of species, and are accumul ... [Soft Matter 6, 4045 (2010)] published Wed Aug 18, 2010.

III-nitride nanopyramid light emitting diodes grown by organometallic vapor phase epitaxy

Isaac H. Wildeson, Robert Colby, David A. Ewoldt, Zhiwen Liang, Dmitri N. Zakharov et al.
Nanopyramid light emitting diodes (LEDs) have been synthesized by selective area organometallic vapor phase epitaxy. Self-organized porous anodic alumina is used to pattern the dielectric growth templates via reactive ion etching, eliminating the need for lithographic processes. (In,Ga)N quantum wel ... [J. Appl. Phys. 108, 044303 ] published .

Cutting Ice: Nanowire Regelation

Teemu Hynninen, Vili Heinonen, Cristiano L. Dias, Mikko Karttunen, Adam S. Foster et al.
Even below its normal melting temperature, ice melts when subjected to high pressure and refreezes once the pressure is lifted. A classic demonstration of this regelation phenomenon is the passing of a thin wire through a block of ice when sufficient force is exerted. Here we present a molecular-dyn ... [Phys. Rev. Lett. 105, 086102 ] published .

A discrete interaction model/quantum mechanical method for describing response properties of molecules adsorbed on metal nanoparticles

Seth Michael Morton and Lasse Jensen
A new polarizable quantum mechanics/molecular mechanics method for the calculation of response properties of molecules adsorbed on metal nanoparticles is presented. This method, which we denote the discrete interaction model/quantum mechanics (DIM/QM) method, represents the nanoparticle atomisticall ... [J. Chem. Phys. 133, 074103 (2010)] published Wed Aug 18, 2010.

Electronic and magnetic properties of zigzag graphene nanoribbons with periodic protruded edges

Wenzhi Wu, Zhuhua Zhang, Peng Lu, and Wanlin Guo
The electronic and magnetic properties of zigzag graphene nanoribbons with protruded steps along their edges (ZS-GNRs) are investigated by extensive density-functional theory calculations. We show that the electronic and magnetic properties are determined by an interesting interplay between the leng ... [Phys. Rev. B 82, 085425 ] published .

Tunable edge magnetism at graphene/graphane interfaces

Manuel J. Schmidt and Daniel Loss
We study the magnetic properties of graphene edges and graphene/graphane interfaces under the influence of electrostatic gates. For this an effective one-dimensional low-energy theory for the edge states, which is derived from the Hubbard model of the honeycomb lattice, is used. We first study the e ... [Phys. Rev. B 82, 085422 ] published .

Surface electronic structure of ZrB buffer layers for GaN growth on Si wafers

Yukiko Yamada-Takamura, Fabio Bussolotti, Antoine Fleurence, Sambhunath Bera, and Rainer Friedlein
The electronic structure of epitaxial, predominantly single-crystalline thin films of zirconium diboride (ZrB), a lattice-matching, conductive ceramic to GaN, grown on Si(111) was studied using angle-resolved ultraviolet photoelectron spectroscopy. The existence of Zr-derived surface states dispersi ... [Appl. Phys. Lett. 97, 073109 (2010)] published Wed Aug 18, 2010.

A charge pumping technique to identify biomolecular charge polarity using a nanogap embedded biotransistor

Sungho Kim, Jee-Yeon Kim, Jae-Hyuk Ahn, Tae Jung Park, Sang Yup Lee et al.
Charge pumping technique is investigated to identify biomolecular charge polarity using a nanogap-embedded biotransistor. Biomolecules immobilized in a nanogap provide additional charges in the gate dielectric. They give rise to a change in the charge pumping current, as detected by applying a desig ... [Appl. Phys. Lett. 97, 073702 (2010)] published Thu Aug 19, 2010.

Polymer templated nanocrystalline titania network for solid state dye sensitized solar cells

Johannes C. Brendel, Yan Lu, and Mukundan Thelakkat
We report a novel preparation method for nanocrystalline TiO networks with controlled pore sizes using spherical polyelectrolyte brushes (SPB) as templates. The SPB consists of a solid polystyrene core from which anionic polyelectrolytes are densely grafted. The SPB templates are synthesized via con ... [J. Mater. Chem. 20, 7255 (2010)] published Wed Aug 18, 2010.

Organic heterojunction photodiodes exhibiting low voltage, imaging-speed photocurrent gain

William T. Hammond and Jiangeng Xue
We report the demonstration of fast and strong photocurrent gain in organic photodiodes with tailored charge blocking layers. The hole blocking layer between the anode and the photoactive layer leads to accumulation of photogenerated holes at its interface with the active layer, which causes a stron ... [Appl. Phys. Lett. 97, 073302 (2010)] published Wed Aug 18, 2010.

Control of Pathways and Yields of Protein Crystallization through the Interplay of Nonspecific and Specific Attractions

Stephen Whitelam
We use computer simulation to study crystal-forming model proteins equipped with interactions that are both orientationally specific and nonspecific. Distinct dynamical pathways of crystal formation can be selected by tuning the strengths of these interactions. When the nonspecific interaction is st ... [Phys. Rev. Lett. 105, 088102 ] published .

Effect of peptide orientation on electron transfer

Bushra R. Chaudhry, James D. E. T. Wilton-Ely, Alethea B. Tabor, and Daren J. Caruana
We have developed a methodology for the in situ derivatisation of histidine residues in self-assembled monolayers of peptides with redox-active groups, and have shown by electrochemical methods that the average dipole of peptide films on gold affects the heterogeneous electron transfer properties. ... [Phys. Chem. Chem. Phys. 12, 9996 (2010)] published Thu Aug 19, 2010.

Supramolecular assembly and small molecule recognition by genetically engineered protein block polymers composed of two SADs

Jennifer S. Haghpanah, Carlo Yuvienco, Eric W. Roth, Alice Liang, Raymond S. Tu et al.
Genetically engineered protein block polymers are an important class of biomaterials that have gained significant attention in recent years due to their potential applications in biotechnology, electronics and medicine. The majority of the protein materials have been composed of at least a single se ... [Mol. BioSyst. 6, 1662 (2010)] published Wed Aug 18, 2010.

Design and construction of an organic crystal with a novel interpenetrated n-Borromean linked topology

Yong-Biao Men, Junliang Sun, Zhi-Tang Huang, and Qi-Yu Zheng
An organic crystal has been designed and constructed by the hydrogen-bond-directed self-assembly of TCA and dpyb, which possesses the large honeycomb net with 5.1 x 5.1 nm cavities and a novel interpenetrated n-Borromean linked topology. ... [Chem. Commun. 46, 6299 ] published .

Self-assembly in binary mixtures of dipolar colloids: Molecular dynamics simulations

Amit Goyal, Carol K. Hall, and Orlin D. Velev
Dipolar colloid particles tend to align end-to-end and self-assemble into micro- and nanostructures, including gels and cocrystals depending on external conditions. We use molecular dynamics computer simulation to explore the phase behavior including formation, structure, crystallization, and/or gel ... [J. Chem. Phys. 133, 064511 (2010)] published Fri Aug 13, 2010.

Transforming spherical block polyelectrolyte micelles into free-suspending films via DNA complexation-induced structural anisotropy

Cong Liu, Kaka Zhang, Daoyong Chen, Ming Jiang, and Shiyong Liu
The deliberately prepared one ssDNA/one micelle complex has an unstable toroidal DNA-bound region and stable upper and lower hemispheres, and thus can self-assemble along the plane of the unstable toroidal region into free-suspending films. ... [Chem. Commun. 46, 6135 (2010)] published Wed Aug 18, 2010.

Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures

Roman M. Lutchyn, Jay D. Sau, and S. Das Sarma
We propose and analyze theoretically an experimental setup for detecting the elusive Majorana particle in semiconductor-superconductor heterostructures. The experimental system consists of one-dimensional semiconductor wire with strong spin-orbit Rashba interaction embedded into a superconducting qu ... [Phys. Rev. Lett. 105, 077001 ] published .

Entanglement Entropy and Entanglement Spectrum of the Kitaev Model

Hong Yao and Xiao-Liang Qi
In this Letter, we obtain an exact formula for the entanglement entropy of the ground state and all excited states of the Kitaev model. Remarkably, the entanglement entropy can be expressed in a simple separable form S=S+S, with S the entanglement entropy of a free Majorana fermion system and S that ... [Phys. Rev. Lett. 105, 080501 ] published .

Spin Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot

Jose Garcia Coello, Abolfazl Bayat, Sougato Bose, John H. Jefferson, and Charles E. Creffield
We exploit the nondissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the Affleck-Kennedy ... [Phys. Rev. Lett. 105, 080502 ] published .

Implications of simultaneous requirements for low-noise exchange gates in double quantum dots

Erik Nielsen, Ralph W. Young, Richard P. Muller, and M. S. Carroll
Achieving low-error, exchange-interaction operations in quantum dots for quantum computing imposes simultaneous requirements on the exchange energy's dependence on applied voltages. A double quantum dot qubit, approximated with a quadratic potential, is solved using a full configuration interaction ... [Phys. Rev. B 82, 075319 ] published .

Quantum-information approach to the quantum phase transition in the Kitaev honeycomb model

Jian Cui, Jun-Peng Cao, and Heng Fan
The Kitaev honeycomb model with a topological phase transition at zero temperature is studied using the quantum-information method. Based on the exact solution of the ground state, the mutual information between two nearest sites and between two bonds with the greatest distance are obtained. It is f ... [Phys. Rev. A 82, 022319 ] published .

Communication at the quantum speed limit along a spin chain

Michael Murphy, Simone Montangero, Vittorio Giovannetti, and Tommaso Calarco
Spin chains have long been considered as candidates for quantum channels to facilitate quantum communication. We consider the transfer of a single excitation along a spin-1/2 chain governed by Heisenberg-type interactions. We build on the work of Balachandran and Gong [V. Balachandran and J. Gong, P ... [Phys. Rev. A 82, 022318 ] published .

Different entanglement dynamical behaviors due to initial system-environment correlations

Ying-Jie Zhang, Xu-Bo Zou, Yun-Jie Xia, and Guang-Can Guo
We theoretically analyze the roles of initial correlations between a two-qubit system and a structured environment on entanglement dynamics of these two qubits. Considering two initial system-environment correlations, we show that the system-environment quantum correlation can initially increase the ... [Phys. Rev. A 82, 022108 ] published .

Local strain in tunneling transistors based on graphene nanoribbons

Yang Lu and Jing Guo
A band-to-band tunneling field-effect transistor (FET) can achieve a subthreshold slope steeper than 60 mV/dec at room temperature, but the on-current is low due to existence of the tunneling barrier. Graphene has a monolayer-thin body which is amenable to strain. By using self-consistent quantum tr ... [Appl. Phys. Lett. 97, 073105 (2010)] published Tue Aug 17, 2010.

High current density, low threshold field emission from functionalized carbon nanotube bucky paper

Bhalchandra A. Kakade, Vijayamohanan K. Pillai, Dattatray J. Late, Padmakar G. Chavan, Farid J. Sheini et al.
Field emission studies of bucky paper of multiwalled carbon nanotubes (MWNTs), prepared after microwave (MW) assisted acid functionalization are reported along with a comparison with that of as-grown sample. MW treated bucky papers reveal an interesting linear field emission behavior in FowlerNordhe ... [Appl. Phys. Lett. 97, 073102 (2010)] published Mon Aug 16, 2010.

Structure of single-wall peptide nanotubes: in situ flow aligning X-ray diffraction

Valeria Castelletto, David R. Nutt, Ian W. Hamley, Seyda Bucak, Celen Cenker et al.
The structure of single wall peptide nanotubes is presented for the model surfactant-like peptide AK. Capillary flow alignment of a sample in the nematic phase at high concentration in water leads to oriented X-ray diffraction patterns. Analysis of these, accompanied by molecular dynamics simulation ... [Chem. Commun. 46, 6270 ] published .

Band gap control of small bundles of carbon nanotubes using applied electric fields: A density functional theory study

Gunn Kim, J. Bernholc, and Young-Kyun Kwon
Electrostatic screening between carbon nanotubes (CNTs) in a small CNT bundle leads to a switching behavior induced by electric field perpendicular to the bundle axis. Using a first-principles method, we investigate the electronic structures of bundles consisting of two or three CNTs and the effects ... [Appl. Phys. Lett. 97, 063113 (2010)] published Fri Aug 13, 2010.

Nonlinear broadband photoluminescence of graphene induced by femtosecond laser irradiation

Wei-Tao Liu, S. W. Wu, P. J. Schuck, M. Salmeron, Y. R. Shen et al.
Upon femtosecond laser irradiation, a bright, broadband photoluminescence is observed from graphene at frequencies well above the excitation frequency. Analyses show that it arises from radiative recombination of a broad distribution of nonequilibrium electrons and holes, generated by rapid scatteri ... [Phys. Rev. B 82, 081408 ] published .

Growth of carbon nanotubes through selective deposition of nanoparticles

Xavier Joyeux, Souad Ammar, Jean Dijon, and Jean Pinson
This paper describes the selective growth of a high density of Carbon NanoTubes (CNTs) (up to 2.5 10 CNT cm) in nanometric (140 to 300 nm) holes etched in silicon dioxide (vias). The method involves (i) the electrografting of a thin layer of poly(hydroxyethyl methacrylate) (polyHEMA) at the Si botto ... [J. Mater. Chem. 20, 7197 (2010)] published Wed Aug 18, 2010.

Terahertz sensing with carbon nanotube layers coated on silica fibers: Carrier transport versus nanoantenna effects

Dalius Seliuta, Irmantas Kasalynas, Jan Macutkevic, Gintaras Valusis, Mikhail V. Shuba et al.
Carbon nanotube layers prepared as coatings on silica fibers are found to be suitable for terahertz detection in 0.57.3 THz range within temperatures of 4.270 K. In time-domain of terahertz excitation, two following constituents in the photoresponse are discriminated: the first one is attributed to ... [Appl. Phys. Lett. 97, 073116 (2010)] published Thu Aug 19, 2010.

A study on the modulation of the electrical transport by mechanical straining of individual titanium dioxide nanotube

A. Asthana, T. Shokuhfar, Q. Gao, P. Heiden, C. Friedrich et al.
We report here, the deformation driven modulation of the electrical transport properties of an individual TiO nanotube via in situ transmission electron microscopy (TEM) using a scanning tunneling microscopy system. The current-voltage characteristics of each individual TiO nanotube revealed that un ... [Appl. Phys. Lett. 97, 072107 (2010)] published Tue Aug 17, 2010.

High temperature Luttinger liquid conductivity in carbon nanotube bundles

B. A. Danilchenko, L. I. Shpinar, N. A. Tripachko, E. A. Voitsihovska, S. E. Zelensky et al.
The conductance and the current-voltage characteristics of metallic single wall carbon nanotube bundles have been measured between 4.2 and 330 K using 1030 ns electric pulses to avoid overheating. The current-voltage characteristics at different temperatures collapse to a single curve when plotted i ... [Appl. Phys. Lett. 97, 072106 (2010)] published Tue Aug 17, 2010.

High Q optomechanical resonators in silicon nitride nanophotonic circuits

K. Y. Fong, W. H. P. Pernice, Mo Li, and H. X. Tang
We demonstrate integrated photonic circuits made from stoichiometric silicon nitride for effective integration of high Q micromechanical resonators and nano-optical components. Using silicon bulk micromachining techniques we fabricate free-standing highly tensile nanostrings exceeding 400 [mu]m in ... [Appl. Phys. Lett. 97, 073112 (2010)] published Wed Aug 18, 2010.

Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays

Antoine-Emmanuel Saliba, Laure Saias, Eleni Psychari, Nicolas Minc, Damien Simon et al.
We propose a unique method for cell sorting, "Ephesia," using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the applica ... [Proc. Natl. Acad. Sci. U.S.A. 107, 14524 (2010)] published Wed Aug 18, 2010.

Heat transfer and fluid flow in microchannels and nanochannels at high Knudsen number using thermal lattice-Boltzmann method

J. Ghazanfarian and A. Abbassi
The present paper deals with the two-dimensional numerical simulation of gaseous flow and heat transfer in planar microchannel and nanochannel with different wall temperatures in transitional regime 0.1<=Kn<=1. An atomistic molecular simulation method is used known as thermal lattice-Boltzmann metho ... [Phys. Rev. E 82, 026307 ] published .

Two-dimensional moveable optical pinhole with applications in single-detector imaging systems

L. Li
A MEMS electromagnetic driven 2D platform that is used to move an optical pinhole has been designed, fabricated, and characterised. The device is powered by Lorentz forces generated from current-varying wires in a magnetic field. A silicon-on-insulator micromachining process was used for the device ... [Electron. Lett. 46, 1215 (2010)] published Wed Aug 18, 2010.

Chiral luminescent CdS nano-tetrapods

Joseph E. Govan, Edward Jan, Ana Querejeta, Nicholas A. Kotov, and Yurii K. Gun'ko
The utilisation of chiral penicillamine stabilisers allowed the preparation of new water soluble white emitting CdS nano-tetrapods, which demonstrated circular dichroism in the band-edge region of the spectrum. ... [Chem. Commun. 46, 6072 (2010)] published Wed Aug 18, 2010.

Demonstration of mode splitting in an optical microcavity in aqueous environment

Woosung Kim, Şahin Kaya Ozdemir, Jiangang Zhu, Lina He, and Lan Yang
Scatterer induced modal coupling and the consequent mode splitting in a whispering gallery mode resonator is demonstrated in aqueous environment. The rate of change in splitting as particles enter the resonator mode volume strongly depends on the concentration of particle solution. The higher is the ... [Appl. Phys. Lett. 97, 071111 (2010)] published Wed Aug 18, 2010.

Room temperature single nanowire ZnTe photoconductors grown by metal-organic chemical vapor deposition

Zhong Li, Joseph Salfi, Christina De Souza, Ping Sun, Selvakumar V. Nair et al.
Single nanowire ZnTe photoconductors prepared by metal-organic chemical vapor deposition are presented. These photodetectors exhibit the highest reported visible responsivity of 360 A/W (at 530 nm) and gain of 8640 (at 3 V bias). The high gain reflects a long carrier lifetime (i.e., ~1 [mu]s) and t ... [Appl. Phys. Lett. 97, 063510 (2010)] published Fri Aug 13, 2010.

Effect of optical feedback to the ground and excited state emission of a passively mode locked quantum dot laser

Charis Mesaritakis, Christos Simos, Hercules Simos, Spiros Mikroulis, Igor Krestnikov et al.
We present an experimental study on the effect of optical feedback in both ground and excited emission of a GaAs quantum dot passively mode locked laser. The experimental setup consisted of a long external cavity with variable cavity length and feedback level ranging from 50 to 20dB. The obtained ex ... [Appl. Phys. Lett. 97, 061114 (2010)] published Fri Aug 13, 2010.

Enhanced tunability of the multiphoton absorption cross-section in seeded CdSe/CdS nanorod heterostructures

Guichuan Xing, Sabyasachi Chakrabortty, Kok Loong Chou, Nimai Mishra, Cheng Hon Alfred Huan et al.
We present a method to separately tune the multiphoton absorption (MPA) and multiphoton excited photoluminescence using semiconductor core/enlarged-shell quantum dots (QDs), where the enlarged shell greatly enhances the MPA cross-sections while varying the core size facilitates emission wavelength s ... [Appl. Phys. Lett. 97, 061112 (2010)] published Fri Aug 13, 2010.

Surface plasmon-enhanced light emission using silver nanoparticles embedded in ZnO

X. H. Xiao, F. Ren, X. D. Zhou, T. C. Peng, W. Wu et al.
The Ag nanoparticles-SiOZnO film sandwiched structure was fabricated by depositing ZnO films on silica substrates which had been implanted by Ag ions. Enhancement of emission of the sandwiched structure was observed. The enhancement emission is caused by the resonant coupling between the surface pla ... [Appl. Phys. Lett. 97, 071909 (2010)] published Thu Aug 19, 2010.

Unidirectional Emission of a Quantum Dot Coupled to a Nanoantenna

Alberto G. Curto, Giorgio Volpe, Tim H. Taminiau, Mark P. Kreuzer, Romain Quidant et al.
Nanoscale quantum emitters are key elements in quantum optics and sensing. However, efficient optical excitation and detection of such emitters involves large solid angles because their interaction with freely propagating light is omnidirectional. Here, we present unidirectional emission of a single ... [Science 329, 930 ] published .

Theory of quantum dot spin lasers

Rafal Oszwaldowski, Christian Gothgen, and Igor Zutic
We formulate a model of a semiconductor quantum dot laser with injection of spin-polarized electrons. As compared to higher-dimensionality structures, the quantum dot based active region is known to improve laser properties, including the spin-related ones. The wetting layer, from which carriers are ... [Phys. Rev. B 82, 085316 ] published .

Excitonic Aharonov-Bohm effect in isotopically pure Ge/Si self-assembled type-II quantum dots

Satoru Miyamoto, Oussama Moutanabbir, Toyofumi Ishikawa, Mikio Eto, Eugene E. Haller et al.
We report on a magnetophotoluminescence study of isotopically pure Ge/Si self-assembled type-II quantum dots. Oscillatory behaviors attributed to the Aharonov-Bohm effect are simultaneously observed for the emission energy and intensity of excitons subject to an increasing magnetic field. When the m ... [Phys. Rev. B 82, 073306 ] published .

Ab initio optoelectronic properties of SiGe nanowires: Role of many-body effects

Maurizia Palummo, Michele Amato, and Stefano Ossicini
The self-energy and electron-hole interaction corrections to the one-particle approximation for SiGe nanowires have been calculated for different geometries and diameters. We show that, at fixed nanowire diameter and orientation, the self-energy corrections for the SiGe nanowires can be obtained as ... [Phys. Rev. B 82, 073305 ] published .

Control of resonance fluorescence in coupled quantum dots

Gao-xiang Li, Shao-ping Wu, and Jia-pei Zhu
Spectral and squeezing properties of the resonance fluorescence of two coupled quantum dots forming an effective Lambda-type three-level structure and connected with two normal metal leads are studied. We assume that one of the dots is driven by a strong light field and find that by modulating the b ... [J. Opt. Soc. Am. B 27, 1634 (2010)] published Fri Aug 13, 2010.

Fabrication and photoluminescence of ZnS:Mn nanowires/ZnO quantum dots/SiO heterostructure

Jinghai Yang, Jian Cao, Lili Yang, Yongjun Zhang, Yaxin Wang et al.
In this paper, we demonstrated the encapsulation of ZnS:Mn nanowires (NWs) and ZnO quantum dots (QDs) with a layer of mesoporous SiO shell for the purpose of integrating dual emission property into one common nanostructure. The average diameter of ZnS:Mn NWs, ZnO QDs, and ZnS:Mn/ZnO@SiO heterostruct ... [J. Appl. Phys. 108, 044304 (2010)] published Wed Aug 18, 2010.

Design and characterization of a field-switchable nanomagnetic atom mirror

T. J. Hayward, A. D. West, K. J. Weatherill, P. J. Curran, P. W. Fry et al.
We present a design for a switchable nanomagnetic atom mirror formed by an array of 180 degrees domain walls confined within NiFe planar nanowires. A simple analytical model is developed which allows the magnetic field produced by the domain wall array to be calculated. This model is then used to o ... [J. Appl. Phys. 108, 043906 (2010)] published Wed Aug 18, 2010.

InGaN/GaN nanorod array white light-emitting diode

Hon-Way Lin (林弘偉), Yu-Jung Lu (呂宥蓉), Hung-Ying Chen (陳虹穎), Hong-Mao Lee (李弘貿), and Shangjr Gwo (果尚志)
Conventional InGaN/GaN light-emitting diodes based on planar quantum well structures do not allow for efficient long-wavelength operation beyond the blue region due to a strong quantum confined Stark effect in lattice-mismatched polar InGaN quantum wells. Here we overcome the limitation by using sel ... [Appl. Phys. Lett. 97, 073101 (2010)] published Mon Aug 16, 2010.

Determination of diffusion lengths in nanowires using cathodoluminescence

Anders Gustafsson, Jessica Bolinsson, Niklas Skold, and Lars Samuelson
We used cathodoluminescence imaging to determine diffusion lengths in III-V semiconductor nanowires, grown by metal-organic chemical vapor deposition seeded by gold nanoparticles. Intensity profiles were recorded either from the interface between the substrate and homogeneous nanowires, or from segm ... [Appl. Phys. Lett. 97, 072114 (2010)] published Thu Aug 19, 2010.

Composite metal/quantum-dot nanoparticle-array waveguides with compensated loss

Petter Holmstrom, Lars Thylen, and Alexander Bratkovsky
We calculate the dispersion properties of waveguides composed of near-field-coupled arrays of metal-clad quantum dots (QDs). The high optical loss incurred by operating the metal shells close to resonance is mitigated by using optical gain in the QDs. A condition for achieving loss compensated opera ... [Appl. Phys. Lett. 97, 073110 (2010)] published Wed Aug 18, 2010.

Incorporating polaritonic effects in semiconductor nanowire waveguide dispersion

Lambert K. van Vugt, Brian Piccione, and Ritesh Agarwal
We present the calculated and measured energy-propagation constant (E-beta) dispersion of CdS nanowire waveguides at room temperature, where we include dispersive effects via the exciton-polariton model using physical parameters instead of a phenomenological equation. The experimental data match wel ... [Appl. Phys. Lett. 97, 061115 (2010)] published Fri Aug 13, 2010.

In vivo imaging and treatment of solid tumor using integrated photoacoustic imaging and high intensity focused ultrasound system

Huizhong Cui and Xinmai Yang
Purpose: The purpose of this study is to show the feasibility of combined contrast imaging and treatment of solid tumor in vivo by an integrated photoacoustic imaging and high intensity focused ultrasound (HIFU) system.Methods: During this study, photoacoustic imaging was performed to identify the l ... [Med. Phys. 37, 4777 (2010)] published Thu Aug 19, 2010.

Second harmonic generating (SHG) nanoprobes for in vivo imaging

Periklis Pantazis, James Maloney, David Wu, and Scott E. Fraser
Fluorescence microscopy has profoundly changed cell and molecular biology studies by permitting tagged gene products to be followed as they function and interact. The ability of a fluorescent dye to absorb and emit light of different wavelengths allows it to generate startling contrast that, in the ... [Proc. Natl. Acad. Sci. U.S.A. 107, 14535 (2010)] published Wed Aug 18, 2010.

Topographic imaging of convoluted surface of live cells by scanning ion conductance microscopy in a standing approach mode

Yasufumi Takahashi, Yumi Murakami, Kuniaki Nagamine, Hitoshi Shiku, Shigeo Aoyagi et al.
Scanning ion conductance microscopy (SICM) using a nanopipette as a probe and ionic current as a feedback signal was introduced as a novel technique to study live cells in a physiological environment. To avoid contact between the pipette tip and cells during the conventional lateral scanning mode, w ... [Phys. Chem. Chem. Phys. 12, 10012 (2010)] published Thu Aug 19, 2010.

Note: Multiscale scanning probe microscopy

L. Chassagne, S. Blaize, P. Ruaux, S. Topcu, P. Royer et al.
Combining the nanoscopic and macroscopic worlds is a serious challenge common to numerous scientific fields, from physics to biology. In this paper, we demonstrate nanometric resolution over a millimeter range by means of atomic-force microscopy using metrological stage. Nanometric repeatability and ... [Rev. Sci. Instrum. 81, 086101 (2010)] published Mon Aug 16, 2010.

Second-harmonic generation in tapered optical fibers

Simon Richard
We present a theoretical study of second-harmonic generation (SHG) in tapered optical fibers in the continuous wave and monochromatic regimes. The mechanism is based on modal phase matching, where the taper is used to sweep the phase mismatch across the phase-matched condition during the propagation ... [J. Opt. Soc. Am. B 27, 1504 (2010)] published Fri Aug 13, 2010.

Dark-field light scattering imaging of living cancer cell component from birth through division using bioconjugated gold nanoprobes

Wei Qian, Xiaohua Huang, Bin Kang, and Mostafa A. El-Sayed
Novel methods and technologies that could extend and complement the capabilities of the prevailing fluorescence microscope in following the cell cycle under different perturbations are highly desirable in the area of biological and biomedical imaging. We report a newly designed instrument for long-t ... [J. Biomed. Opt. 15, 046025 (2010)] published Fri Aug 13, 2010.

Near-field optical data storage using C-apertures

J. Brian Leen, Paul Hansen, Yao-Te Cheng, Aaron Gibby, and Lambertus Hesselink
We demonstrate the all-optical recording of deeply subwavelength data bits in GeSbTe using a near-field scanning optical microscope (NSOM) probe that utilizes a C-aperture fabricated using through membrane focused ion beam milling. Data bits recorded with various optical powers were read out optical ... [Appl. Phys. Lett. 97, 073111 (2010)] published Wed Aug 18, 2010.

Publisher's Note: Vertex Dynamics in Finite Two-Dimensional Square Spin Ices [Phys. Rev. Lett. 105, 017201 (2010)]

Zoe Budrikis, Paolo Politi, and R. L. Stamps
Abstract not available. [Phys. Rev. Lett. 105, 089901 ] published .

Effective Low-Energy Model for f-Electron Delocalization

K. A. Al-Hassanieh, Yi-feng Yang, Ivar Martin, and C. D. Batista
We consider a periodic Anderson model (PAM) with a momentum-dependent interband hybridization that is strongly suppressed near the Fermi level. Under these conditions, we reduce the PAM to an effective low-energy Hamiltonian, H, by expanding in the small parameter V/t (V is the maximum interband hyb ... [Phys. Rev. Lett. 105, 086402 ] published .

Impact on Interface Spin Polarization of Molecular Bonding to Metallic Surfaces

S. Javaid, M. Bowen, S. Boukari, L. Joly, J.-B. Beaufrand et al.
We have studied the repercussion of the molecular adsorption mechanism on the electronic properties of the interface between model nonmagnetic or magnetic metallic surfaces and metallo-organic phthalocyanines molecules (Pcs). Our intertwined x-ray absorption spectroscopy experiments and computationa ... [Phys. Rev. Lett. 105, 077201 ] published .

Orbital selective and tunable Kondo effect of magnetic adatoms on graphene: Correlated electronic structure calculations

D. Jacob and G. Kotliar
We have studied the effect of dynamical correlations on the electronic structure of single Co adatoms on graphene monolayers with a recently developed method for nanoscopic materials that combines density-functional calculations with a fully dynamical treatment of the strongly interacting 3d electro ... [Phys. Rev. B 82, 085423 ] published .

Magneto-optical control of a Mn nano-magnet

Eric Riviere, Bertrand Donnio, Emilie Voirin, Guillaume Rogez, Jean-Paul Kappler et al.
Single-Molecule Magnets (SMMs) are much investigated for the development of high-density information storage systems or the implementation of quantum algorithms for computation. For both applications the control of the magnetic state is paramount. So far only partial success at achieving such an aim ... [J. Mater. Chem. 20, 7165 (2010)] published Wed Aug 18, 2010.

Fast high fidelity hole spin initialization in a single InGaAs quantum dot

T. M. Godden, S. J. Boyle, A. J. Ramsay, A. M. Fox, and M. S. Skolnick
We demonstrate fast initialization of a single hole spin trapped in an InGaAs quantum dot with a fidelity F>99% and a 1/e time of ~30 ps, by applying a magnetic field parallel to the growth direction. We show that the fidelity of the hole spin, prepared by ionization of a photo-generated electron-h ... [Appl. Phys. Lett. 97, 061113 (2010)] published Fri Aug 13, 2010.

Quantum oscillations in a molecular magnet

S. Bertaina, S. Gambarelli, T. Mitra, B. Tsukerblat, A. Mller et al.
Abstract not available. [Nature 466, 1006 (2010)] published Thu Aug 19, 2010.

A strong ferroelectric ferromagnet created by means of spinlattice coupling

June Hyuk Lee, Lei Fang, Eftihia Vlahos, Xianglin Ke, Young Woo Jung et al.
Ferroelectric ferromagnets are exceedingly rare, fundamentally interesting multiferroic materials that could give rise to new technologies in which the low power and high speed of field-effect electronics are combined with the permanence and routability of voltage-controlled ferromagnetism. Further ... [Nature 466, 954 (2010)] published Thu Aug 19, 2010.

Low-frequency noise in strained SiGe core-shell nanowire p-channel field effect transistors

Doyoung Jang, Jae Woo Lee, Kiichi Tachi, Laurent Montes, Thomas Ernst et al.
Low-frequency noise has been studied in compressively strained SiGe core-shell nanowire (NW) p-channel transistors compared with unstrained NWs. The noise has been well interpreted using the carrier number with correlated mobility fluctuation model. The volume trap density, N, lies in the range of 2 ... [Appl. Phys. Lett. 97, 073505 (2010)] published Thu Aug 19, 2010.

Thermal conductivity in metallic nanostructures at high temperature: Electrons, phonons, and the Wiedemann-Franz law

N. Stojanovic, D. H. S. Maithripala, J. M. Berg, and M. Holtz
The Boltzmann transport equation is used to calculate thermal and electrical conductivity of metal nanostructures with characteristic dimensions in the 25500 nm range, near to and above the Debye temperature. Thermal conductivity contributions from phonons and electrons are considered. The intrinsic ... [Phys. Rev. B 82, 075418 ] published .

Tuning Fano resonances by magnetic forces for electron transport through a quantum wire side coupled to a quantum ring

B. Szafran and M. R. Poniedzialek
We consider electron transport in a quantum wire with a side-coupled quantum ring in a two-dimensional model that accounts for a finite width of the channels. We use the finite difference technique to solve the scattering problem as well as to determine the ring-localized states of the energy contin ... [Phys. Rev. B 82, 075320 ] published .

Interference, Coulomb blockade, and the identification of non-Abelian quantum Hall states

Ady Stern, Bernd Rosenow, Roni Ilan, and Bertrand I. Halperin
We study electronic-transport phenomena in a Fabry-Perot interferometer in the fractional quantum Hall regime in two limits. We analyze the lowest-order interference pattern in a nearly open interferometer (weak-backscattering limit) and the temperature dependence of the Coulomb-blockade transmissio ... [Phys. Rev. B 82, 085321 ] published .

Electrically induced n-i-p junctions in multiple graphene layer structures

M. Ryzhii, V. Ryzhii, T. Otsuji, V. Mitin, and M. S. Shur
The Fermi energies of electrons and holes and their densities in different graphene layers (GLs) in the n and p regions of the electrically induced n-i-p junctions formed in multiple-GL structures are calculated both numerically and using a simplified analytical model. The reverse current associated ... [Phys. Rev. B 82, 075419 ] published .

Metallization of Nanofilms in Strong Adiabatic Electric Fields

Maxim Durach, Anastasia Rusina, Matthias F. Kling, and Mark I. Stockman
We introduce an effect of metallization of dielectric nanofilms by strong, adiabatically varying electric fields. The metallization causes optical properties of a dielectric film to become similar to those of a plasmonic metal (strong absorption and negative permittivity at low optical frequencies). ... [Phys. Rev. Lett. 105, 086803 ] published .

Low-noise submicron channel graphene nanoribbons

Guangyu Xu, Jingwei Bai, Carlos M. Torres, Jr., Emil B. Song, Jianshi Tang et al.
We present a graphene nanoribbon fabrication method based on a nanowire mask. Using a four-probe setup, single-layer nanoribbon (SLR) and bilayer nanoribbon (BLR) show low-frequency noise levels lower than (comparable to) the SLRs (BLRs) achieved by hydrogen-silsesquioxane based methods. Submicron c ... [Appl. Phys. Lett. 97, 073107 (2010)] published Wed Aug 18, 2010.

Large thermoelectric figure of merit for three-dimensional topological Anderson insulators via line dislocation engineering

O. A. Tretiakov, Ar. Abanov, Shuichi Murakami, and Jairo Sinova
We study the thermoelectric properties of three-dimensional topological Anderson insulators with line dislocations. We show that at high densities of dislocations the thermoelectric figure of merit ZT can be dominated by one-dimensional topologically protected conducting states channeled through the ... [Appl. Phys. Lett. 97, 073108 (2010)] published Wed Aug 18, 2010.

Pyroelectric scanning probe microscopy: A method for local measurement of the pyroelectric effect in ferroelectric thin films

J. Groten, M. Zirkl, G. Jakopic, A. Leitner, and B. Stadlober
This work demonstrates a surface scanning method for the quantitative determination of the local pyroelectric coefficient in ferroelectric thin films. It allows generating a map of the pyroelectric response with very high spatial resolution. In domains of previously aligned dipole moments (achieved ... [Phys. Rev. B 82, 054112 ] published .

Electron microscopy of GaAs/MnAs core/shell nanowires

N. S. Dellas, J. Liang, B. J. Cooley, N. Samarth, and S. E. Mohney
GaAs/MnAs core/shell nanowire heterostructures were synthesized by catalyst-free molecular beam epitaxy. Transmission electron microscopy (TEM) reveals that the GaAs core predominantly grows with the zinc-blende crystal structure with a [111] growth direction. In a small population of wires, the cry ... [Appl. Phys. Lett. 97, 072505 (2010)] published Wed Aug 18, 2010.

Suppression of Octahedral Tilts and Associated Changes in Electronic Properties at Epitaxial Oxide Heterostructure Interfaces

A. Y. Borisevich, H. J. Chang, M. Huijben, M. P. Oxley, S. Okamoto et al.
Epitaxial oxide interfaces with broken translational symmetry have emerged as a central paradigm behind the novel behaviors of oxide superlattices. Here, we use scanning transmission electron microscopy to demonstrate a direct, quantitative unit-cell-by-unit-cell mapping of lattice parameters and ox ... [Phys. Rev. Lett. 105, 087204 ] published .

Microscopic Observation of Kinetic Molecular Sieving of Hydrogen Isotopes in a Nanoporous Material

T. X. Nguyen, H. Jobic, and S. K. Bhatia
We report quasielastic neutron scattering studies of H-D diffusion in a carbon molecular sieve, demonstrating remarkable quantum effects, with the heavier isotope diffusing faster below 100 K, confirming our recent predictions. Our transition state theory and molecular dynamics calculations show tha ... [Phys. Rev. Lett. 105, 085901 ] published .

Submicron Plasticity: Yield Stress, Dislocation Avalanches, and Velocity Distribution

Peter Dusan Ispanovity, Istvan Groma, Geza Gyorgyi, Ferenc F. Csikor, and Daniel Weygand
The existence of a well-defined yield stress, where a macroscopic crystal begins to plastically flow, has been a basic observation in materials science. In contrast with macroscopic samples, in microcrystals the strain accumulates in random bursts, which makes controlled plastic formation difficult. ... [Phys. Rev. Lett. 105, 085503 ] published .

Tunable heat pump by modulating the coupling to the leads

Eduardo C. Cuansing and Jian-Sheng Wang
We follow the nonequilibrium Green's function formalism to study time-dependent thermal transport in a linear chain system consisting of two semi-infinite leads connected together by a coupling that is harmonically modulated in time. The modulation is driven by an external agent that can absorb and ... [Phys. Rev. E 82, 021116 ] published .

Coherent elastic waves in a one-dimensional polymer hypersonic crystal

P. M. Walker, J. S. Sharp, A. V. Akimov, and A. J. Kent
Using the methods of picosecond acoustics, we inject high amplitude hypersonic wavepackets into a polymer superlattice and optically detect the propagating coherent elastic waves. The spectrum of the optically detected signal shows the elastic modes typical for folded phonon dispersion curves. The e ... [Appl. Phys. Lett. 97, 073106 (2010)] published Tue Aug 17, 2010.