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2009-02-10
Spontaneous and low-field magnetoimpedance in La0.7Sr0.3CoO3 and La1-xSrxMnO3 (x = 0.18-0.5)
We report ac electrical transport in La0.7Sr0.3CoO3 and La1-xSrxMnO3 (x = 0.18- 0.5) as a function of temperature and frequency in H = 0 and 60 mT. Both resistive (R) and reactive (X) components of impedance (Z = R+jX) were measured. It is shown that a smooth decrease of the resistance around the Curie temperautre in L...
0902.1780v1
2009-04-24
Evolution of orbital phases with particle size in nanoscale stoichiometric LaMnO3
The thermodynamically stable long-range orbital order in bulk LaMnO3 becomes metastable at nanoscale around a critical particle size d_C~20 nm. The orbital order-disorder transition switches from reversible to irreversible at d_C while the resistance in the orbital ordered state decays by 2-4% over a time scale of ~300...
0904.3878v3
2009-06-04
Sensitivity of Ag/Al Interface Specific Resistances to Interfacial Intermixing
We have measured an Ag/Al interface specific resistance, 2AR(Ag/Al)(111) = 1.4 fOhm-m^2, that is twice that predicted for a perfect interface, 50% larger than for a 2 ML 50%-50% alloy, and even larger than our newly predicted 1.3 fOhmm^2 for a 4 ML 50%-50% alloy. Such a large value of 2ARAg/Al(111) confirms a predicted...
0906.0934v1
2009-06-04
Perpendicular-current Studies of Electron Transport Across Metal/Metal Interfaces
We review what we have learned about the scattering of electrons by the interfaces between two different metals (M1/M2) in the current-perpendicular-to-plane (CPP) geometry. In this geometry, the intrinsic quantity is the specific resistance, AR, the product of the area through which the CPP current flows times the CPP...
0906.0936v1
2009-06-26
Upper bound for the conductivity of nanotube networks
Films composed of nanotube networks have their conductivities regulated by the junction resistances formed between tubes. Conductivity values are enhanced by lower junction resistances but should reach a maximum that is limited by the network morphology. By considering ideal ballistic-like contacts between nanotubes we...
0906.4906v2
2009-06-29
Upper critical fields of the 11-system iron-chalcogenide superconductor FeSe$_{0.25}$Te$_{0.75}$
We have performed electrical resistivity measurements of a polycrystalline sample of FeSe$_{0.25}$Te$_{0.75}$, which exhibits superconductivity at $T_{\rm c} \sim 14$ K, in magnetic fields up to 55 T to determine the upper critical field $\mu_{0}H_{\rm c2}$. In this compound, very large slopes of $\mu_{0}H_{\rm c2}$ at...
0906.5248v1
2009-07-17
Phase diagram of CeFeAs$_{1-x}$P$_{x}$O obtained from electric resistivity, magnetization, and specific heat measurements
We performed a systematic study on the properties of CeFeAs$_{1-x}$P$_{x}$O ($0\leq x\leq 1$) by electrical resistivity, magnetization and specific heat measurements. The c-axis lattice constant decreases significantly with increasing P content, suggesting a remarkable chemical pressure. The Fe-3d electrons show the en...
0907.2961v2
2009-07-31
Top and side gated epitaxial graphene field effect transistors
Three types of first generation epitaxial graphene field effect transistors (FET) are presented and their relative merits are discussed. Graphene is epitaxially grown on both the carbon and silicon faces of hexagonal silicon carbide and patterned with electron beam lithography. The channels have a Hall bar geometry to ...
0908.0017v1
2009-08-02
Spin-dependent transport in nanocomposite C:Co films
The magneto-transport properties of nanocomposite C:Co (15 and 40 at.% Co) thin films are investigated. The films were grown by ion beam co-sputtering on thermally oxidized silicon substrates in the temperature range from 200 to 500 degC. Two major effects are reported: (i) a large anomalous Hall effect amounting to 2 ...
0908.0127v1
2009-09-16
Superconductivity at 39 K in New Iron Pnictide Oxide (Fe2As2)(Sr4(Mg,Ti)2O6)
We have discovered a new iron pnictide oxide superconductor (Fe2As2)(Sr4(Mg,Ti)2O6). This material is isostructual with (Fe2As2)(Sr4M2O6) (M = Sc, Cr), which was found in our previous study. The structure of this compound is tetragonal with a space group of P4/nmm and consists of the anti-fluorite type FeAs and perovsk...
0909.2945v3
2009-09-25
Electrical, magnetic, magnetodielectric and magnetoabsorption studies in multiferroic GaFeO3
We report electrical, magnetic, magnetodielectric and magnetoabsorption properties of a polycrystalline GaFeO3. The resistivity measurement shows that the sample is highly insulating below 200 K and the resistivity above 200 K obey the Arrhenius law with an activation energy of Ea = 0.67 eV. An anomaly occurs in the te...
0909.4609v1
2009-10-11
Anomalous Hall resistance in Ge:Mn systems with low Mn concentrations
Taking Mn doped Germanium as an example, we evoke the consideration of a two-band-like conduction in diluted ferromagnetic semiconductor (FMS). The main argument for claiming Ge:Mn as a FMS is the occurrence of the anomalous Hall effect (AHE). Usually, the reported AHE (1) is observable at temperatures above 10 K, (2) ...
0910.1981v1
2009-10-20
Sharp fall of electrical resistance for a small application of magnetic field on a metastable form of a compound, Tb5Si3, under pressure
We report an unusual sensitivity of electrical resistivity (rho) to an application of a small magnetic field in an intermetallic compound, Tb5Si3, under pressure. In this compound, there is a magnetic field-induced first-order magnetic transition at 1.8 K. Under pressure, there is a metastable magnetic phase after redu...
0910.3794v1
2009-11-11
Neutron powder diffraction investigation of the structural and magnetic properties of (La1-yYy)FeAsO
The structural, magnetic and resistive properties of (La1-yYy)FeAsO compounds (y = 0.10, 0.20, 0.30) have been investigated by means of X-ray and neutron powder diffraction as well as by resistivity measurements. The temperatures at which the structural transition from tetragonal to orthorhombic and the magnetic orderi...
0911.2153v1
2009-11-23
Magnetic field and contact resistance dependence of non-local charge imbalance
Crossed Andreev reflection (CAR) in metallic nanostructures, a possible basis for solid-state electron entangler devices, is usually investigated by detecting non-local voltages in multi-terminal superconductor/normal metal devices. This task is difficult because other subgap processes may mask the effects of CAR. One ...
0911.4427v1
2009-12-16
Cooling dynamics and thermal interface resistance of glass-embedded metal nanoparticles
The cooling dynamics of glass-embedded noble metal nanoparticles with diameters ranging from 4 to 26 nm were studied using ultrafast pump-probe spectroscopy. Measurements were performed probing away from the surface plasmon resonance of the nanoparticles to avoid spurious effects due to glass heating around the particl...
0912.3058v1
2009-12-29
Interplay of bulk and interface effects in the electric-field driven transition in magnetite
Contact effects in devices incorporating strongly-correlated electronic materials are comparatively unexplored. We have investigated the electrically-driven phase transition in magnetite (100) thin films by four-terminal methods. In the lateral configuration, the channel length is less than 2 $\mu$m, and voltage-probe ...
0912.5374v1
2010-01-08
Low-magnetic-field control of dielectric constant at room temperature realized in Ba0.5Sr1.5Zn2Fe12O22
We show that room temperature resistivity of Ba0.5Sr1.5Zn2Fe12O22 single crystals increases by more than three orders of magnitude upon being subjected to optimized heat treatments. The increase in the resistivity allows the determination of magnetic field (H)-induced ferroelectric phase boundaries up to 310 K through ...
1001.1319v1
2010-03-05
Weak superconducting fluctuations and small anisotropy of the upper critical fields in an Fe1.05Te0.85Se0.15 single crystal
We have investigated the temperature dependence of the resistive upper critical fields ($\mu_{0}H_{\rm c2}(T)$) for an Fe$_{1.05}$Te$_{0.85}$Se$_{0.15}$ single crystal, which exhibit superconductivity at $T_{\rm c} \sim 14 K, in magnetic fields of up to 55 T. Two-dimensional feature and superconducting fluctuations of ...
1003.1171v3
2010-03-19
Lateral Spin Injection in Germanium Nanowires
Electrical injection of spin-polarized electrons into a semiconductor, large spin diffusion length, and an integration friendly platform are desirable ingredients for spin-based devices. Here we demonstrate lateral spin injection and detection in germanium nanowires, by using ferromagnetic metal contacts and tunnel bar...
1003.3787v2
2010-03-28
Scanning Gate Microscopy on Graphene: Charge Inhomogeneity and Extrinsic Doping
We have performed scanning gate microscopy (SGM) on graphene field effect transistors (GFET), using a biased metallic nanowire coated with a dielectric layer as a contact mode tip and local top gate. Electrical transport through graphene at various back gate voltages is monitored as a function of tip voltage and tip po...
1003.5404v1
2010-04-07
Temperature dependence of the nonlocal voltage in an Fe/GaAs electrical spin injection device
The nonlocal spin resistance is measured as a function of temperature in a Fe/GaAs spin-injection device. For nonannealed samples that show minority-spin injection, the spin resistance is observed up to room temperature and decays exponentially with temperature at a rate of 0.018\,K$^{-1}$. Post-growth annealing at 440...
1004.1034v1
2010-05-01
Reversible Fluorination of Graphene: towards a Two-Dimensional Wide Bandgap Semiconductor
We report the synthesis and evidence of graphene fluoride, a two-dimensional wide bandgap semiconductor derived from graphene. Graphene fluoride exhibits hexagonal crystalline order and strongly insulating behavior with resistance exceeding 10 G$\Omega$ at room temperature. Electron transport in graphene fluoride is we...
1005.0113v1
2010-07-15
Quantum Hall Resistance Overshoot in 2-Dimensional Electron Gases - Theory and Experiment
We present a systematical experimental investigation of an unusual transport phenomenon observed in two dimensional electron gases in Si/SiGe heterostructures under integer quantum Hall effect (IQHE) conditions. This phenomenon emerges under specific experimental conditions and in different material systems. It is comm...
1007.2586v1
2010-08-10
Transition from a ferromagnetic insulating to a ferromagnetic metallic state in nanoparticles of Nd0.8Sr0.2MnO3 : Study of the electronic - and magneto - transport properties
A detailed investigation of the electronic - and magneto - transport properties of Nd0.8Sr0.2MnO3 with the variation of grain size (down to 42 nm) is presented here. Interestingly, we observe that the ferromagnetic insulating state is suppressed and a metallic state is stabilized as the grain size of the sample is redu...
1008.1693v1
2010-08-18
A New Strained-Silicon Channel Trench-gate Power MOSFET: Design and Analysis
In this paper, we propose a new trench power MOSFET with strained Si channel that provides lower on resistance than the conventional trench MOSFET. Using a 20% Ge mole fraction in the Si1-xGex body with a compositionally graded Si1-xGex buffer in the drift region enables us to create strain in the channel along with gr...
1008.3019v1
2010-08-24
Dominant role of impurity scattering over crystalline anisotropy for magnetotransport properties in the quasi-1D Hollandite Ba1.2Rh8O16
Angular magnetotransport measurements have been performed to tackle the origin of the magnetoresistance in the quasi-1D Hollandite Ba1.2Rh8O16. Three samples of different impurities amount were measured. We observe that the low temperature resistivity upturn is not due to a charge density wave transition, and a dominan...
1008.4040v1
2010-09-27
Effect of vertex corrections on the longitudinal transport through multilayered nanostructures: Exact dynamical mean-field theory approach applied to the inhomogeneous Falicov-Kimball model
Inhomogeneous dynamical mean-field theory is employed to calculate the vertex-corrected electronic charge transport for multilayered devices composed of semi-infinite metallic lead layers coupled through a strongly correlated material barrier region. The barrier region can be tuned from a metal to a Mott insulator thro...
1009.5299v1
2010-10-08
A unified first-principles study of Gilbert damping, spin-flip diffusion and resistivity in transition metal alloys
Using a formulation of first-principles scattering theory that includes disorder and spin-orbit coupling on an equal footing, we calculate the resistivity $\rho$, spin flip diffusion length $l_{sf}$ and the Gilbert damping parameter $\alpha$ for Ni$_{1-x}$Fe$_x$ substitutional alloys as a function of $x$. For the techn...
1010.1626v3
2010-10-23
Silicon Oxide is a Non-Innocent Surface for Molecular Electronics and Nanoelectronics Studies
Silicon oxide (SiOx) has been widely used in many electronic systems as a supportive and insulating medium. Here we demonstrate various electrical phenomena such as negative differential resistance, resistive switching and current hysteresis intrinsic to a thin layer of SiOx. These behaviors can largely mimic numerous ...
1010.4853v1
2010-11-17
Oxidation resistance of graphene-coated Cu and Cu/Ni alloy
The ability to protect refined metals from reactive environments is vital to many industrial and academic applications. Current solutions, however, typically introduce several negative effects, including increased thickness and changes in the metal physical properties. In this paper, we demonstrate for the first time t...
1011.3875v1
2010-12-20
Conduction Electron Scattering and Spin-Flipping at Sputtered Co/Ni Interfaces
Current-perpendicular-to-plane magnetoresistance (CPP-MR) measurements let us quantify conduction electron scattering and spin-flipping at a sputtered ferromagnetic/ferromagnetic (F1/F2 = Co/Ni) interface, with important consequences for CPP-MR and spin-torque experiments with perpendicular anisotropy. We use ferromagn...
1012.4388v1
2011-01-19
Negative differential resistance in scanning tunneling microscopy: simulations on C$_{60}$-based molecular overlayers
We determine the conditions in which negative differential resistance (NDR) appears in the C$_{60}$-based molecular device of [Phys. Rev. Lett. {\bf 100}, 036807 (2008)] by means of ab-initio electron-transport simulations. Our calculations grant access to bias-dependent intrinsic properties of the molecular device, su...
1101.3714v1
2011-01-26
Metal-insulator transition in ultrathin LaNiO3 films
Transport in ultrathin films of LaNiO3 evolves from a metallic to a strongly localized character as the film's thickness is reduced and the sheet resistance reaches a value close to h/e2, the quantum of resistance in two dimensions. In the intermediate regime, quantum corrections to the Drude low- temperature conductiv...
1101.5111v2
2011-03-31
Aharonov-Casher effect in Bi$_{\rm 2}$Se$_{\rm 3}$ square-ring interferometers
Electrical control of spin dynamics in Bi$_{\rm 2}$Se$_{\rm 3}$ was investigated in ring-type interferometers. Aharonov-Bohm and Altshuler-Aronov-Spivak resistance oscillations against magnetic field, and Aharorov-Casher resistance oscillations against gate voltage were observed in the presence of a Berry phase of $\pi...
1103.6115v1
2011-06-02
Evidence for semiconducting behavior with a narrow band gap of Bernal graphite
We have studied the resistivity of a large number of highly oriented graphite samples with areas ranging from several mm$^2$ to a few $\mu$m$^2$ and thickness from $\sim 10 $nm to several tens of micrometers. The measured resistance can be explained by the parallel contribution of semiconducting graphene layers with lo...
1106.0437v3
2011-07-25
Unveiling a nematic quantum critical point in multi-orbital systems
Electronic nematicity, proposed to exist in a number of transition metal materials, can have different microscopic origins. In particular, the anisotropic resistivity and meta-magnetic jumps observed in Sr3Ru2O7 are consistent with an earlier proposal that the isotropic-nematic transition is generically first order and...
1107.5052v5
2011-08-25
Structural and Electrical Characterization of Bi2Se3 Nanostructures Grown by Metalorganic Chemical Vapor Deposition
We characterize nanostructures of Bi2Se3 that are grown via metalorganic chemical vapor deposition using the precursors diethyl selenium and trimethyl bismuth. By adjusting growth parameters, we obtain either single-crystalline ribbons up to 10 microns long or thin micron-sized platelets. Four-terminal resistance measu...
1108.4978v2
2011-09-14
Growth of atomically smooth thin films of the electronically phase separated manganite (La$_{0.5}$Pr$_{0.5}$)$_{0.67}$Ca$_{0.33}$MnO$_{3}$
Atomically flat, epitaxial, and stoichiometric thin films of the electronically phase separated compound (La$_{0.5}$Pr$_{0.5}$)$_{0.67}$Ca$_{0.33}$MnO$_{3}$ were grown on as-received and treated NdGaO$_{3}$ substrates by fine tuning of oxygen pressure during deposition. Optimal thin films with step flow growth mode sho...
1109.3225v1
2011-09-23
A single layer hydrogen silsesquioxane (HSQ) based lift-off process for germanium and platinum
Primarily used as etch mask, single layer hydrogen silsesquioxane has never been investigated for lift-off technique. In this article, we propose a new technique where a single layer of hydrogen silsesquioxane, a negative tone electron beam resist, is used to make lift-off of germanium and platinum. Removal of exposed ...
1109.5187v1
2011-11-03
Estimation of the spin polarization for Heusler-compound thin films by means of nonlocal spin-valve measurements: Comparison of Co$_{2}$FeSi and Fe$_{3}$Si
We study room-temperature generation and detection of pure spin currents using lateral spin-valve devices with Heusler-compound electrodes, Co$_{2}$FeSi (CFS) or Fe$_{3}$Si (FS). The magnitude of the nonlocal spin-valve (NLSV) signals is seriously affected by the dispersion of the resistivity peculiarly observed in the...
1111.0742v2
2011-11-27
A first-order magnetic phase transition near 15 K with novel magnetic-field-induced effects in Er5Si3
We present magnetic characterization of a binary rare-earth intermetallic compound Er5Si3, crystallizing in Mn5Si3-type hexagonal structure, through magnetization, heat-capacity, electrical resistivity, and magnetoresistance measurements. Our investigations confirm that the compound exhibits two magnetic transitions wi...
1111.6240v1
2011-12-20
Approximate Theory of Temperature Coefficient of Resistivity of Amorphous Semiconductors
In this paper, we develop an approximate theory of the temperature coefficient of resistivity (TCR) and conductivity based upon the recently proposed Microscopic Response Method. By introducing suitable approximations for the lattice dynamics, localized and extended electronic states, we produce new explicit forms for ...
1112.4723v2
2011-12-23
Microscopic Details of the Integer Quantum Hall Effect in an Anti-Hall Bar
Due to the lack of simulation tools that take into account the actual geometry of complicated quantum Hall samples there are lots of experiments that are not yet fully understood. Already some years ago R. G. Mani recorded a shift of the Hall resistance transitions to lower magnetic fields in samples of a Hall bar with...
1112.5673v1
2012-02-27
Coaxial Nanowire Resonant Tunneling Diodes from non-polar AlN/GaN on Silicon
Resonant tunneling diodes are formed using AlN/GaN core-shell nanowire heterostructures grown by plasma assisted molecular beam epitaxy on n-Si(111) substrates. By using a coaxial geometry these devices take advantage of non-polar (m-plane) nanowire sidewalls. Device modeling predicts non-polar orientation should enhan...
1202.6052v2
2012-04-09
Magnetic-field induced resistivity minimum with in-plane linear magnetoresistance of the Fermi liquid in SrTiO3-x single crystals
We report novel magnetotransport properties of the low temperature Fermi liquid in SrTiO3-x single crystals. The classical limit dominates the magnetotransport properties for a magnetic field perpendicular to the sample surface and consequently a magnetic-field induced resistivity minimum emerges. While for the field a...
1204.1901v1
2012-04-20
Size-dependent electronic-transport mechanism and sign reversal of magnetoresistance in Nd0.5Sr0.5CoO3
A detailed investigation of electronic-transport properties of Nd0.5Sr0.5CoO3 has been carried out as a function of grain size ranging from micrometer order down to an average size of 28 nm. Interestingly, we observe a size induced metal-insulator transition in the lowest grain size sample while the bulk-like sample is...
1204.4572v1
2012-04-22
Anomalous ferromagnetism and non-Fermi-liquid behavior in the Kondo lattice CeRuSi2
The structural, electronic and magnetic properties of the Kondo-lattice system CeRuSi2 are experimentally investigated and analyzed in the series of other ternary cerium compounds. This system is shown to be an excellent model system demonstrating coexistence of the Kondo effect and anomalous ferromagnetism with a smal...
1204.4903v3
2012-07-02
Evolution of the magnetism of Tb(Co_{x}Ni_{1-x})_{2}B_{2}C
The magnetic properties of polycrystalline Tb(Co_{x}Ni_{1-x})_{2}B_{2}C (x=0.2,0.4,0.6,0.8) samples were probed by magnetization, specific heat, ac susceptibility, and resistivity techniques. For x{\neq}0.4, the obtained curves are consistent with the features expected for the corresponding magnetic modes, namely k_{1}...
1207.0519v1
2012-07-19
Mobility enhancement and highly efficient gating of monolayer MoS2 transistors with Polymer Electrolyte
We report electrical characterization of monolayer molybdenum disulfide (MoS2) devices using a thin layer of polymer electrolyte consisting of poly(ethylene oxide) (PEO) and lithium perchlorate (LiClO4) as both a contact-barrier reducer and channel mobility booster. We find that bare MoS2 devices (without polymer elect...
1207.4824v1
2012-07-20
Magnetic, magnetocaloric and magnetotransport properties of RSn_{1+x}Ge_{1-x} compounds (R=Gd, Tb, Er; x=0.1)
We have studied the magnetic, magnetocaloric and magnetotransport properties of RSn1+xGe1-x(R=Gd, Tb, Er; x=0.1) series by means of magnetization, heat capacity and resistivity measurements. It has been found that all the compounds crystallize in the orthorhombic crystal structure described by the centrosymmetric space...
1207.4971v1
2012-07-30
The Effect of Electrode Size on Memristor Properties: An Experimental and Theoretical Study
The width of the electrodes is not included in the current phenomenological models of memristance, but is included in the memory-conservation (mem-con) theory of memristance. An experimental study of the effect of changing the top electrode width was performed on titanium dioxide sol-gel memristors. It was demonstrated...
1207.6933v1
2012-08-06
A Variant of the Point Defect Model for Passivity of Metals
A variant of the point defect model originally enunciated by Macdonald and co-workers is advanced and its theoretical implications for the steady state current density, barrier layer thickness and the concentration of metal vacancy at the metal/film interface are deduced. The differences between the original point defe...
1208.1096v1
2012-08-27
Suppression of superconductivity in layered Bi4O4S3 by Ag doping
We report X-ray diffraction, magnetization and transport measurements for polycrystalline samples of the new layered superconductor Bi4-xAgxO4S3 (0<x<0.2). The superconducting transition temperature (TC) decreases gradually and finally suppressed for x>0.10. Accordingly, the resistivity changes from a metallic behavior...
1208.5307v1
2012-09-27
Theoretical investigation of direct and phonon-assisted tunneling currents in InAlGaAs-InGaAs bulk and quantum well interband tunnel junctions for multi-junction solar cells
Direct and phonon-assisted tunneling currents in InAlGaAs-InGaAs bulk and double quantum well interband tunnel heterojunctions are simulated rigorously using the non-equilibrium Green's function formalism for coherent and dissipative quantum transport in combination with a simple two-band tight-binding model for the el...
1209.6314v1
2012-10-11
Prediction of semi-metallic tetragonal Hf2O3 and Zr2O3 from first-principles
A tetragonal phase is predicted for Hf2O3 and Zr2O3 using density functional theory. Starting from atomic and unit cell relaxations of substoichiometric monoclinic HfO2 and ZrO2, such tetragonal structures are only reached at zero temperature by introducing the oxygen vacancy pair with the lowest formation energy. The ...
1210.3348v1
2012-10-12
Superconducting LaAlO3/SrTiO3 Nanowires
We report superconductivity in quasi-1D nanostructures created at the LaAlO3/SrTiO3 interface. Nanostructures having line widths w~10 nm are formed from the parent two-dimensional electron liquid using conductive atomic force microscope lithography. Nanowire cross-sections are small compared to the superconducting cohe...
1210.3606v1
2012-10-26
Spin injection from a half-metal at finite temperatures
Spin injection from a half-metallic electrode in the presence of thermal spin disorder is analyzed using a combination of random matrix theory, spin-diffusion theory, and explicit simulations for the tight-binding s-d model. It is shown that efficient spin injection from a half-metal is possible as long as the effectiv...
1210.7194v2
2012-12-03
Resistive switching in ferroelectric BiFeO3 by 1.7 eV change of the Schottky barrier height
Using metal-ferroelectric junctions as switchable diodes was proposed several decades ago. This was shown to actually work in PbZr(1-x)TixO3 (PZT) by Blom et al. [P.W. M. Blom et al., Phys. Rev. Lett. 73, 2107 (1994)], who reported switching in the rectification direction and changes of the current of about 2 orders of...
1212.0483v1
2012-12-18
Low temperature transport properties of multigraphene structures on 6H-SiC obtained by thermal graphitization: evidences of a presence of nearly perfect graphene layer
Transport properties of multigraphene layers on 6H-SiC substrates fabricated by thermal graphitization of SiC were studied. The principal result is that these structures were shown to contain a nearly perfect graphene layer situated between the SiC substrate and multgraphene layer. It was found that the curves of magne...
1212.4272v1
2013-01-07
Quantum Hall Effect in Hydrogenated Graphene
The quantum Hall effect is observed in a two-dimensional electron gas formed in millimeter-scale hydrogenated graphene, with a mobility less than 10 $\mathrm{cm^{2}/V\cdot s}$ and corresponding Ioffe-Regel disorder parameter $(k_{F}\lambda)^{-1}\gg1$. In zero magnetic field and low temperatures, the hydrogenated graphe...
1301.1257v1
2013-01-12
Magnetic field-tuned Aharonov-Bohm oscillations and evidence for non-Abelian anyons at v=5/2
We show that the resistance of the v=5/2 quantum Hall state, confined to an interferometer, oscillates with magnetic field consistent with an Ising-type non-Abelian state. In three quantum Hall interferometers of different sizes, resistance oscillations at v=7/3 and integer filling factors have the magnetic field perio...
1301.2639v1
2013-02-07
Thermal Conductivity and Phonon Transport in Suspended Few-Layer Hexagonal Boron Nitride
The thermal conductivity of suspended few-layer hexagonal boron nitride (h-BN) was measured using a micro-bridge device with built-in resistance thermometers. Based on the measured thermal resistance values of 11-12 atomic layer h-BN samples with suspended length ranging between 3 and 7.5 um, the room-temperature therm...
1302.1890v1
2013-02-08
Comparative study of the electronic structure, phonon spectra and electron-phonon interaction of ZrB2 and TiB2
The electronic structure, optical and x-ray absorption spectra, angle dependence of the cyclotron masses and extremal cross sections of the Fermi surface, phonon spectra, electron-phonon Eliashberg and transport spectral functions, temperature dependence of electrical resistivity of the MB2 (M=Ti and Zr) diborides were...
1302.2144v1
2013-02-15
Storing magnetic information in IrMn/MgO/Ta tunnel junctions via field-cooling
Tunneling junctions containing no ferromagnetic elements have been fabricated and we show that distinct resistance states can be set by field cooling the devices from above the N\'eel along different orientations. Variations of the resistance up to 10% are found upon field cooling in applied fields of 2T, in-plane or o...
1302.3837v1
2013-03-06
Highly reproducible metal/graphene contacts and stable electrical performance by UV-Ozone treatment
Resist residue from the device fabrication process is a general and significant source of the metal/graphene contact interface contamination. In this paper, Ultraviolet-Ozone (UVO) treatment is proven to be an effective way of cleaning the metal/graphene interface. Electrical measurements of devices, which were fabrica...
1303.1353v2
2013-03-15
Thermoelectric Properties of Polycrystalline NiSi3P4
The Hall and Seebeck coefficients, electrical resistivity and thermal conductivity of polycrystalline NiSi3P4 were characterized from 2 to 775K. Undoped NiSi3P4 behaves like a narrow gap semiconductor, with activated electrical resistivity \rho below room temperature and a large Seebeck coefficient of ~400uV/K at 300K....
1303.3772v1
2013-03-29
Hysteretic superconducting resistive transition in Ba0.07K0.93Fe2As2
We have observed hysteresis in superconducting resistive transition curves of Ba$_{0.07}$K$_{0.93}$Fe$_2$As$_2$ ($T_c\sim$8 K) below about 1 K for in-plane fields. The hysteresis is not observed as the field is tilted away from the $ab$ plane by 20$^{\circ}$ or more. The temperature and angle dependences of the upper c...
1303.7281v4
2013-04-04
Benchtop Fabrication of Memristive Atomic Switch Networks
Recent advances in nanoscale science and technology provide possibilities to directly self-assemble and integrate functional circuit elements within the wiring scheme of devices with potentially unique architectures. Electroionic resistive switching circuits comprising highly interconnected fractal electrodes and metal...
1304.1243v2
2013-04-08
Ultra Low Power Associative Computing with Spin Neurons and Resistive Crossbar Memory
Emerging resistive-crossbar memory (RCM) technology can be promising for computationally-expensive analog pattern-matching tasks. However, the use of CMOS analog-circuits with RCM would result in large power-consumption and poor scalability, thereby eschewing the benefits of RCM-based computation. We propose the use of...
1304.2281v1
2013-04-28
Hidden Fermi Liquid, Scattering Rate Saturation and Nernst Effect: a DMFT Perspective
We investigate the transport properties of a correlated metal within dynamical mean field theory. Canonical Fermi liquid behavior emerges only below a very low temperature scale $T_{FL}$. Surprisingly the quasiparticle scattering rate follows a quadratic temperature dependence up to much higher temperatures and crosses...
1304.7486v1
2013-05-10
Geometric treatment of conduction electron scattering by crystal lattice strains and dislocations
A theory for conduction electron scattering by inhomogeneous crystal lattice strains is developed, based on the differential geometric treatment of deformations in solids. The resulting fully covariant Schr\"odinger equation shows that the electrons can be described as moving in a non-Euclidean background space in the ...
1305.2455v3
2013-05-15
Origin of Rigidity in Dry Granular Solids
Solids are distinguished from fluids by their ability to resist shear. In traditional solids, the resistance to shear is associated with the emergence of broken translational symmetry as exhibited by a non-uniform density pattern. In this work, we focus on the emergence of shear-rigidity in a class of solids where this...
1305.3484v2
2013-06-24
Polarization Controlled Ohmic to Schottky Transition at a Metal/Doped Ferroelectric Interface
Ferroelectric polar displacements have recently been observed in conducting electron-doped BaTiO3. The co-existence of a ferroelectric phase and conductivity opens the door to new functionalities which may provide a unique route for novel device applications. Using first-principles methods and electrostatic modeling we...
1306.5763v2
2013-07-04
Impact of intrinsic deformations on the negative differential resistance of monolayer MoS$_2$ ultra-short channel MOSFET
In this work we present a study on the impact of various intrinsic deformations like ripples, twist, wrap on the electronic properties of ultra-short monolayer MoS2 channels. The effect of deformation (3-7o twist or wrap and 0.3-0.7 buckling amplitude) on a 3.5 nm planar monolayer MoS2 MOSFET is evaluated by the densit...
1307.1306v2
2013-07-24
Extremely Large Magnetoresistance in the Nonmagnetic Metal PdCoO2
Extremely large magnetoresistance is realized in the nonmagnetic layered metal PdCoO2. In spite of a highly conducting metallic behavior with a simple quasi-two-dimensional hexagonal Fermi surface, the interlayer resistance reaches up to 35000% for the field along the [1-10] direction. Furthermore, the temperature depe...
1307.6503v2
2013-08-08
Magneto-Transport Properties of Single Crystalline LaFeAsO
Measurements of magnetization, specific heat, electrical resistivity, Hall effect, and magnetoresistance on single crystalline samples of LaFeAsO grown in a NaAs flux are reported. While this material is known to be a semimetal, the temperature dependence of the electrical resistivity data presented herein is reminisce...
1308.1885v1
2013-08-20
Probing long-range correlations in the Berezinskii-Kosterlitz-Thouless fluctuation regime of ultra-thin NbN superconducting films using transport noise measurements
We probe the presence of long-range correlations in phase fluctuations by analyzing the higher-order spectrum of resistance fluctuations in ultra-thin NbN superconducting films. The non-Gaussian component of resistance fluctuations is found to be sensitive to film thickness close to the transition, which allows us to d...
1308.4234v2
2013-09-04
Current-Induced Gap Suppression in the Mott Insulator Ca$_2$RuO$_4$
We present nonlinear conduction phenomena in the Mott insulator Ca2RuO4 investigated with a proper evaluation of self-heating effects. By utilizing a non-contact infrared thermometer, the sample temperature was accurately determined even in the presence of large Joule heating. We find that the resistivity continuously ...
1309.0909v1
2013-09-06
Spin density wave order and fluctuations in Mn3Si: a transport study
We present a comprehensive transport investigation of the itinerant antiferromagnet Mn3Si which undergoes a spin density wave (SDW) order below T_N~21.3K. The electrical resistivity, the Hall-, Seebeck and Nernst effects exhibit pronounced anomalies at the SDW transition, while the heat conductivity is phonon dominated...
1309.1636v1
2013-09-06
Metal-insulator transition induced in SrTi_{1-x}V_xO_3 thin films
Epitaxial SrTi1-xVxO3 thin films with thicknesses of ~16 nm were grown on (001)-oriented LSAT substrates using the pulsed electron-beam deposition technique. The transport study revealed a temperature driven metal-insulator transition (MIT) at 95 K for the film with x = 0.67. The films with higher vanadium concentratio...
1309.1745v1
2013-09-10
Magnetoresistance evidence on surface state and field-dependent bulk gap in Kondo insulator SmB6
Recently, the resistance saturation at low temperature in Kondo insulator SmB6, a long-standing puzzle in condensed matter physics, was proposed to originate from topological surface state. Here,we systematically studied the magnetoresistance of SmB6 at low temperature up to 55 Tesla. Both temperature- and angular-depe...
1309.2378v3
2013-09-27
Evidence for a Kondo destroying quantum critical point in YbRh2Si2
The heavy-fermion metal YbRh$_{2}$Si$_{2}$ is a weak antiferromagnet below $T_{N} = 0.07$ K. Application of a low magnetic field $B_{c} = 0.06$ T ($\perp c$) is sufficient to continuously suppress the antiferromagnetic (AF) order. Below $T \approx 10$ K, the Sommerfeld coefficient of the electronic specific heat $\gamm...
1309.7260v1
2013-09-29
An Efficient Authorship Protection Scheme for Shared Multimedia Content
Many electronic content providers today like Flickr and Google, offer space to users to publish their electronic media (e.g. photos and videos) in their cloud infrastructures, so that they can be publicly accessed. Features like including other information, such as keywords or owner information into the digital materia...
1309.7640v1
2013-10-11
Enhanced low-energy magnetic excitations via suppression of the itinerancy in Fe0.98-zCuzTe0.5Se0.5
We have performed resistivity and inelastic neutron scattering measurements on three samples of Fe0.98-zCuzTe0.5Se0.5 with z = 0, 0.02, and 0.1. It is found that with increasing Cu doping the sample's resistivity deviates progressively from that of a metal. However, in contrast to expectations that replacing Fe with Cu...
1310.3064v1
2013-10-28
Emergence of pressure-induced metamagnetic-like state in Mn-doped CdGeAs2 chalcopyrite
The effect of hydrostatic pressure on resistivity and magnetic ac susceptibility has been studied in Mn-doped CdGeAs2 room-temperature (RT) ferromagnetic chalcopyrite with two types of MnAs micro-clusters. The slight increase of temperature by about 30 K in the region between RT and Curie temperature TC causes a signif...
1310.7451v1
2013-12-13
Temperature-dependent structural property and power factor of n type thermoelectric Bi0.90Sb0.10 and Bi0.86Sb0.14 alloys
Thermal variation of structural property, linear thermal expansion coefficient, resistivity, thermopower and power factor of polycrystalline Bi1-xSbx (x=0.10, 0.14) samples are reported. Temperature-dependent powder diffraction experiments indicate that samples do not undergo any structural phase transition. Rietveld r...
1312.3898v1
2014-02-11
Taming the resistive switching in Fe/MgO/V/Fe magnetic tunnel junctions: An ab initio study
A possible mechanism for the resistive switching observed experimentally in Fe/MgO/V/Fe junctions is presented. Ab initio total energy calculations within the local density approximation and pseudopotential theory shows that by moving the oxygen ions across the MgO/V interface one obtains a metastable state. It is argu...
1402.2517v2
2014-02-24
Coplanar waveguide based ferromagnetic resonance in ultrathin film magnetic nanostructures: impact of conducting layers
We report broadband ferromagnetic resonance (FMR) measurements based on a coplanar waveguide (CPW) of ultrathin magnetic film structures that comprise in-plane/out-of-plane decoupled layers deposited on nonmagnetic buffer layers of various thickness or other buffer structures with a diverse sheet resistance. We show th...
1402.5844v2
2014-03-05
Electrical and optical properties of fluid iron from compressed to expanded regime
Using quantum molecular dynamics simulations, we show that the electrical and optical properties of fluid iron change drastically from compressed to expanded regime. The simulation results reproduce the main trends of the electrical resistivity along isochores and are found to be in good agreement with experimental dat...
1403.1030v1
2014-03-06
Correlation between bulk thermodynamic measurements and the low temperature resistance plateau in SmB6
Topological insulators are materials characterized by dissipationless, spin-polarized surface states resulting from non-trivial band topologies. Recent theoretical models and experiments suggest that SmB6 is the first topological Kondo insulator, in which the topologically non-trivial band structure results from electr...
1403.1462v2
2014-03-25
Quantum Resistor-Capacitor Circuit with Majorana Fermion Modes in Chiral Topological Superconductor
We investigate the mesoscopic resistor-capacitor circuit consisting of a quantum dot coupled to spatially separated Majorana fermion modes in a chiral topological superconductor. We find substantially enhanced relaxation resistance due to the nature of Majorana fermions, which are their own anti-particles and composed ...
1403.6239v2
2014-04-26
Electric field control of magnetic properties and magneto-transport in composite multiferroics
We study magnetic state and electron transport properties of composite multiferroic system consisting of a granular ferromagnetic thin film placed above the ferroelectric substrate. Ferroelectricity and magnetism in this case are coupled by the long-range Coulomb interaction. We show that magnetic state and magneto-tra...
1404.6671v2
2014-05-24
Visible light enhanced field effect at LaAlO3/SrTiO3 interface
Electrical field and light-illumination have been two most widely used stimuli in tuning the conductivity of semiconductor devices. Via capacitive effect electrical field modifies the carrier density of the devices, while light-illumination generates extra carriers by exciting trapped electrons into conduction band1. H...
1405.6250v1
2014-06-25
Compressive strain-induced metal-insulator transition in orthorhombic SrIrO3 thin films
We have investigated the electronic properties of epitaxial orthorhombic SrIrO3 thin-films under compressive strain. The metastable, orthorhombic SrIrO3 thin-films are synthesized on various substrates using an epi-stabilization technique. We have observed that as in-plane lattice compression is increased, the dc-resis...
1406.6640v1
2014-06-28
Exceptional Suppression of Flux-Flow Resistivity in FeSe$_{0.4}$Te$_{0.6}$ by Back-Flow from Excess Fe Atoms and Se/Te Substitutions
We measured the microwave surface impedance of FeSe$_{0.4}$Te$_{0.6}$ single crystals with- and without external magnetic fields. The superfluid density exhibited a quadratic temperature dependence, indicating a strong pair-breaking effect. The flux-flow resistivity behaved as $\rho_f(B\ll B_{\rm c2})/\rho_n=\alpha B/B...
1406.7383v2
2014-07-08
Non thermal and purely electronic resistive transition in narrow gap Mott insulators
Mott insulator to metal transitions under electric field are currently the subject of numerous fundamental and applied studies. This puzzling effect, which involves non-trivial out-of-equilibrium effects in correlated systems, is indeed at play in the operation of a new class of electronic memories, the Mott memories. ...
1407.2038v1
2014-12-08
Role of Se vacancies on Shubnikov de Haas oscillations in Bi2Se3: a combined magneto-resistance and positron annihilation study
Magneto resistance measurements coupled with positron lifetime measurements, to characterize the vacancy type defects, have been carried out on the topological insulator (TI) system Bi2Se3, of varying Se/Bi ratio. Pronounced Shubnikov de Haas (SdH) oscillations are seen in nominal Bi2Se3.1 crystals for measurements per...
1412.2466v1
2014-12-08
Effect of Electron-Phonon Coupling on Thermal Transport across Metal-Nonmetal Interface - A Second Look
The effect of electron-phonon (e-ph) coupling on thermal transport across metal-nonmetal interfaces is yet to be completely understood. In this paper, we use a series of molecular dynamics (MD) simulations with e-ph coupling effect included by Langevin dynamics to calculate the thermal conductance at a model metal-nonm...
1412.2791v3
2014-12-15
Percolation conductivity in hafnium sub-oxides
In this study, we demonstrated experimentally that formation of chains and islands of oxygen vacancies in hafnium sub-oxides (HfO$_x$, $x<2$) leads to percolation charge transport in such dielectrics. Basing on the model of \'{E}fros-Shklovskii percolation theory good quantitative agreement between the experimental and...
1412.4478v1