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2006-11-28
Energy Transport between Hole Gas and Crystal Lattice in Diluted Magnetic Semiconductor
The temperature dependent energy transfer rate between charge carriers and lattice has been experimentally investigated in ferromagnetic semiconductors. Studied 100 nm thick low-temperature MBE grown Mn_{x}Ga_{1-x}As samples had manganese concentrations x=3.7 % and 4.0 %. Curie temperatures estimated from temperatures ...
0611704v1
2006-12-01
Vortex motion in chilarity-controlled pair of magnetic disks
We investigate the influence of the vortex chirality on the magnetization processes of a magnetostatically coupled pair of magnetic disks. The magnetic vortices with opposite chiralities are realized by introducing asymmetry into the disks. The motion of the paired vortices are studied by measuring the magnetoresistanc...
0612023v1
2006-12-01
Microscopic and Macroscopic Signatures of Antiferromagnetic Domain Walls
Magnetotransport measurements on small single crystals of Cr, the elemental antiferromagnet, reveal the hysteretic thermodynamics of the domain structure. The temperature dependence of the transport coefficients is directly correlated with the real-space evolution of the domain configuration as recorded by x-ray microp...
0612039v1
2006-12-06
Plasma-Like Negative Capacitance in Nano-Colloids
A negative capacitance has been observed in a nano-colloid between 0.1 and 10^-5 Hz. The response is linear over a broad range of conditions. The low-omega dispersions of both the resistance and capacitance are consistent with the free-carrier plasma model, while the transient behavior demonstrates an unusual energy st...
0612160v1
2006-12-11
Theoretical study of doped-Tl$_{2}$Mn$_{2}$O$_{7}$ and Tl$_{2}$Mn$_{2}$O$_{7}$ under pressure
Using first-principles density functional based calculations, we study the effect of doping and pressure in manganese based pyrochlore compound,Tl$_{2}$Mn$_{2}$O$_{7}$ that exhibits colossal magneto-resistive behavior. The theoretical study is motivated by the counter-intuitive experimental observation of suppression o...
0612245v2
2006-12-31
Thermal rectifying effect in two dimensional anharmonic lattices
We study thermal rectifying effect in two dimensional (2D) systems consisting of the Frenkel Kontorva (FK) lattice and the Fermi-Pasta-Ulam (FPU) lattice. It is found that the rectifying effect is related to the asymmetrical interface thermal resistance. The rectifying efficiency is typically about two orders of magnit...
0701015v1
2007-01-18
On the origin of unusual transport properties observed in densely packed polycrystalline CaAl_{2}
A possible origin of unusual temperature behavior of transport coefficients observed in densely packed polycrystalline CaAl_{2} compound [M. Ausloos et al., J. Appl. Phys. 96, 7338 (2004)] is discussed, including a power-like dependence of resistivity with $\rho \propto T^{-3/4}$ and N-like form of the thermopower. All...
0701456v1
2007-01-24
Graphene Nano-Ribbon Electronics
We have fabricated graphene nano-ribbon field-effect transistor devices and investigated their electrical properties as a function of ribbon width. Our experiments show that the resistivity of a ribbon increases as its width decreases, indicating the impact of edge states. Analysis of temperature dependent measurements...
0701599v1
2007-03-07
Current sharing between superconducting film and normal metal
A two-dimensional model is introduced that describes current sharing between the superconducting and normal metal layers in configuration typical of YBCO-coated conductors. The model is used to compare the effectiveness of surround stabilizer and more conventional one-sided stabilizer. When the resistance of the interf...
0703193v1
2007-03-12
Effect of Polarized Current on the Magnetic State of Antiferromagnet
We provide evidence for the effects of spin polarized current on a nanofabricated antiferromagnet incorporated into a spin-valve structure. Signatures of current-induced effects include bipolar steps in differential resistance, current-induced changes of exchange bias correlated with these steps, and deviations from th...
0703281v2
2007-04-14
Biased Structural Fluctuations due to Electron Wind Force
Direct correlation between temporal structural fluctuations and electron wind force is demonstrated, for the first time, by STM imaging and analysis of atomically-resolved motion on a thin film surface under large applied current (10e5 Amp/sqare cm). The magnitude of the momentum transfer between current carriers and a...
0704.1852v1
2007-04-25
Pressure induced magnetic ordering in Yb2Pd2Sn with two quantum critical points
Pressure induced long range antiferromagnetic order is discovered in Yb2Pd2Sn by measuring the electrical resistivity under pressure up to 5.0 GPa. Magnetic ordering is observed above about 1.0 GPa, being the lowest pressure in Yb-intermetallics showing pressure induced magnetic ordering, Unexpectedly, ordering disappe...
0704.3307v2
2007-06-10
Scattering of charge carriers by point defects in bilayer graphene
Theory of scattering of massive chiral fermions in bilayer graphene by radial symmetric potential is developed. It is shown that in the case when the electron wavelength is much larger than the radius of the potential the scattering cross-section is proportional to the electron wavelength. This leads to the mobility in...
0706.1351v2
2007-06-19
Resistive state of quasi-one-dimensional superconductors: fluctuations vs. sample inhomogeneity
The shape of experimentally observed R(T) transition of thin superconducting wires is analyzed. Broadening of the transition in quasi-1-dimensional superconducting channels is typically associated with phase slip mechanism provided by thermal or quantum fluctuations. It is shown that consideration of inevitable geometr...
0706.2779v1
2007-08-03
Nonlocal Charge Transport Mediated by Spin Diffusion in the Spin-Hall Effect Regime
A nonlocal electric response in the spin-Hall regime, resulting from spin diffusion mediating charge conduction, is predicted. The spin-mediated transport stands out due to its long-range character, and can give dominant contribution to nonlocal resistance. The characteristic range of nonlocality, set by the spin diffu...
0708.0455v1
2007-09-11
Co/Nb/Co low field superconducting spin switch
We report experiments on a superconducting spin switch based on technologically relevant materials as elemental ferromagnetic Co and elemental superconducting Nb. The Co/Nb/Co structure exhibits inverse spin switch effect, can be operated at liquid helium temperature and can switch from superconductive to normal state ...
0709.1687v1
2007-09-12
Dynamic Thermal Analysis of a Power Amplifier
This paper presents dynamic thermal analyses of a power amplifier. All the investigations are based on the transient junction temperature measurements performed during the circuit cooling process. The presented results include the cooling curves, the structure functions, the thermal time constant distribution and the N...
0709.1818v1
2007-09-20
A Kondo lattice antiferromagnet CePd5Al2
We report on the electrical resistivity, magnetic susceptibility and heat-capacity measurements on a new intermetallic compound CePd5Al2, crystallizing in the ZrNi2Al5-type tetragonal structure, with lattice parameters a = 4.156 A and c = 14.883 A. The compound presents Kondo lattice behavior and an easy-plane antiferr...
0709.3135v1
2007-09-24
Magnetoresistance in an all-manganite heterostructure
We study the magnetic and transport properties of all-manganite heterostructures consisting of ferromagnetic metallic electrodes separated by an antiferromagnetic barrier. We find that the magnetic ordering in the barrier is influenced by the relative orientation of the electrodes magnetization producing a large differ...
0709.3720v1
2007-11-06
Barrier breakdown in a multiple quantum well structure
We explore a regime of unipolar electronic transport in a multiple quantum well structure with very large current discontinuities - up to five orders of magnitude. Magneto-transport experiments reveal different transport regimes. Quantum well impact ionization shifts the structure from a resistive down state, where the...
0711.0890v1
2007-11-08
Substrate limited electron dynamics in graphene
We study the effects of polarizable substrates such as SiO2 and SiC on the carrier dynamics in graphene. We find that the quasiparticle spectrum acquires a finite broadening due to the long-range interaction with the polar modes at the interface between graphene and the substrate. This mechanism results in a density de...
0711.1303v3
2007-11-28
Evidence for Two Current Conduction in Iron
Measurements of resistivities of dilute iron based alloys show strong deviations from Matthiessen's rule. These deviations can be explained by a model in which spin up and spin down electrons conduct in parallel. The results are consistent with the theory of impurity shielding in these alloys. [This 1967 paper provides...
0711.4478v1
2007-12-12
Magnetic phase transition and magnetocaloric effect in PrCo9Si4 and NdCo9Si4
The compounds, PrCo9Si4 and NdCo9Si4, have been recently reported to exhibit first-order ferromagnetic transitions near 24 K. We have subjected this compound for further characterization by magnetization, heat-capacity and electrical resistivity measurements at low temperatures in the presence of magnetic fields, parti...
0712.1989v1
2008-01-09
Colossal Positive Magnetoresistance in a Doped Nearly Magnetic Semiconductor
We report on a positive colossal magnetoresistance (MR) induced by metallization of FeSb$_{2}$, a nearly magnetic or "Kondo" semiconductor with 3d ions. We discuss contribution of orbital MR and quantum interference to enhanced magnetic field response of electrical resistivity.
0801.1354v1
2008-03-27
Current-induced persistent magnetization in a relaxorlike manganite
A single crystal of 7% Fe-doped (La$_{0.7}$Pr$_{0.3}$)$_{0.65}$Ca$_{0.35}$MnO$_3$ shows up as a typical relaxor ferromagnet, where ferromagnetic metallic and charge-orbital-ordered insulating clusters coexist with controllable volume fraction by external stimuli. There, the persistent ferromagnetic metallic state can b...
0803.3922v1
2008-03-30
Organized Current Patterns in Disordered Conductors
We present a general theory of current deviations in straight current carrying wires with random imperfections, which quantitatively explains the recent observations of organized patterns of magnetic field corrugations above micron-scale evaporated wires. These patterns originate from the most efficient electron scatte...
0803.4307v1
2008-05-16
Frictional Duality Observed during Nanoparticle Sliding
One of the most fundamental questions in tribology concerns the area dependence of friction at the nanoscale. Here, experiments are presented where the frictional resistance of nanoparticles is measured by pushing them with the tip of an atomic force microscope. We find two coexisting frictional states: While some part...
0805.2448v2
2008-05-28
Extraordinary sensitivity of the electronic structure and properties of single-walled carbon nanotubes to molecular charge-transfer
Interaction of single-walled carbon nanotubes with electron donor and acceptor molecules causes significant changes in the electronic and Raman spectra, the relative proportion of the metallic species increasing on electron donation through molecular charge transfer, as also verified by electrical resistivity measureme...
0805.4239v1
2008-06-10
Thermal contact resistance between two nanoparticles
We compute the thermal conductance between two nanoparticles in contact based on the Molecular Dynamics technique. The contact is generated by letting both particles stick together under van der Waals attractions. The thermal conductance is derived from the fluctuation-dissipation theorem and the time fluctuations of t...
0806.1609v1
2008-06-25
Morphology and flexibility of graphene and few-layer graphene on various substrates
We report on detailed microscopy studies of graphene and few-layer-graphene produced by mechanical exfoliation on various semi-conducting substrates. We demonstrate the possibility to prepare and analyze graphene on (001)-GaAs, manganese p-doped (001)-GaAs and InGaAs substrates. The morphology of graphene on these subs...
0806.4074v1
2008-06-25
Hidden Orbital Liquid State Within Ferromagnetically Ordered Metallic SrRuO3
We have experimentally found related anomalies in electrical resistivity, dc and ac magnetic susceptibility, appearing deeply within ferromagnetically ordered state in SrRuO3. Lack of Jahn-Teller distortion in this regime rules out conventional orbital order, forcing one to describe these in terms of an orbital liquid ...
0806.4198v1
2008-07-29
Control of heat transport in quantum spin systems
We study heat transport in quantum spin systems analytically and numerically. First, we demonstrate that heat current through a two-level quantum spin system can be modulated from zero to a finite value by tuning a magnetic field. Second, we show that a spin system, consisting of two dissimilar parts - one is gapped an...
0807.4575v1
2008-07-31
Superconductivity in nickel-based compound GdONiBi and hole doped Gd0.9Sr0.1ONiBi
We successfully synthesized the nickel-based compound GdONiBi with superconducting transition temperature about 4.5 K. By partially substituting the element Gd with Sr to introduce holes into the material, we got new superconductor Gd0.9Sr0.1ONiBi with critical temperature about 4.7 K. The normal state resistivity in n...
0807.5045v1
2008-09-11
Koshino-Taylor effect in graphene
We discuss the phonon-assisted scattering of electrons by defects, i.e., the so-called Koshino-Taylor effect, in graphene. The two-dimensional character of graphene implies that the strength of the Koshino-Taylor effect can be considerably larger than in ordinary metals. We show that at finite temperatures the defect-i...
0809.1996v2
2008-10-10
Hysteresis in the electronic transport of V2O3 thin films: non-exponential kinetics and range scale of phase coexistence
The thermal hysteresis of the electronic transport properties were studied for V2O3 thin films. The temporal evolution of the resistance shows the out-of-equilibrium nature of this hysteresis with a very slow relaxation. Partial cycles reveal not only a behavior consistent with phase coexistence, but also the presence ...
0810.1868v1
2008-11-19
Nonlocal Spin Transport in Lateral Spin Valves with Multiple Ferromagnetic Electrodes
We study the nonlocal spin transport in a lateral spin valve with multiple ferromagnetic (FM) electrodes. When two current-injecting and two spin current-detecting electrodes are all ferromagnetic, the number of possible nonlocal spin signal states is four at maximum. In reality, this number is reduced, depending on th...
0811.3138v1
2009-02-24
Analysis of the Conduction Heat Transfer in Cantilevers under Steady State Cryogenic Conditions
An accurate analysis of the conduction heat transfer in a cryogenic flask is made and some useful formulae are derived. Taking into account the temperature dependence of conductivity and tensile strength of the supporting rods for a helium cryostat, these formulae may provide more exact results than the the formulae ba...
0902.4144v1
2009-03-23
Spin-polarized electronic structures and transport properties of Fe-Co alloys
The electrical resistivities of Fe-Co alloys owing to random alloy disorder are calculated using the Kubo-Greenwood formula. The obtained electrical esistivities agree well with experimental data quantitatively at low temperature. The spin-polarization of Fe50Co50 estimated from the conductivity (86%) has opposite sign...
0903.3842v1
2009-04-15
Nonvolatile memory effects in hybrid devices of few-layer graphene and ferroelectric polymer films
We report on the fabrication and electrical characterization of few-layer graphene (FLG) devices coated with a ferroelectric polymer layer of poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)]. Highly stable and reliable resistance changes were observed under floating conditions, which were dependent on the back...
0904.2242v1
2009-04-15
Quasiparticle Transformation During a Metal-Insulator Transition in Graphene
Here we show, with simultaneous transport and photoemission measurements, that the graphene terminated SiC(0001) surface undergoes a metal-insulator transition (MIT) upon dosingwith small amounts of atomic hydrogen. We find the room temperature resistance increases by about 4 orders of magnitude, a transition accompani...
0904.2249v1
2009-05-14
Galvanomagnetic properties and noise in a barely metallic film of V2O3
We have measured the magnetotransport properties of a strained metallic V2O3 thin film. Most of the properties are similar to V2O3 single crystals that have been submitted to a large pressure. In addition, resistance noise analysis indicates that conductivity fluctuations are freezing out at T\approx 10K. Examination o...
0905.2290v1
2009-05-25
Photocurrent Properties of Freely Suspended Carbon Nanotubes under Uniaxial Strain
The photocurrent properties of freely suspended single-walled carbon nanotubes (CNTs) are investigated as a function of uniaxial strain. We observe that at low strain, the photocurrent signal of the CNTs increases for increasing strain, while for large strain, the signal decreases, respectively. We interpret the non-mo...
0905.3952v1
2009-06-23
Breakdown Current Density of Graphene Nano Ribbons
Graphene nanoribbons (GNRs) with widths down to 16 nm have been characterized for their current-carrying capacity. It is found that GNRs exhibit an impressive breakdown current density, on the order of 10^8 A/cm2. The breakdown current density is found to have a reciprocal relationship to GNR resistivity and the data f...
0906.4156v1
2009-07-07
Quantum oscillations in a topological insulator Bi_{1-x}Sb_{x}
We have studied transport and magnetic properties of Bi_{1-x}Sb_x, which is believed to be a topological insulator - a new state of matter where an insulating bulk supports an intrinsically metallic surface. In nominally insulating Bi_{0.91}Sb_{0.09} crystals, we observed strong quantum oscillations of the magnetizatio...
0907.1125v1
2009-07-17
Calculation of Cu/Ta interface electron transmission and effect on conductivity in nanoscale interconnect technology
Resistivity augmentation in nanoscale metal interconnects is a performance limiting factor in integrated circuits. Here we present calculations of electron scattering and transmission at the interface between Cu interconnects and their barrier layers, in this case Ta. We also present a semiclassical model to predict th...
0907.2999v2
2009-07-22
Magnetoresistive junctions based on epitaxial graphene and hexagonal boron nitride
We propose monolayer epitaxial graphene and hexagonal boron nitride (h-BN) as ultimate thickness covalent spacers for magnetoresistive junctions. Using a first-principles approach, we investigate the structural, magnetic and spin transport properties of such junctions based on structurally well defined interfaces with ...
0907.3952v1
2009-08-20
Scattering of charge carriers in graphene induced by topological defects
We study the scattering of graphene quasiparticles by topological defects, represented by holes, pentagons and heptagons. For holes, we found that at low concentration they give a negligible contribution to the resistivity. Whenever pentagons or heptagons are introduced we realize that a fermionic current is scattered ...
0908.2979v2
2009-08-31
Tuning the graphene work function by electric field effect
We report variation of the work function for single and bi-layer graphene devices measured by scanning Kelvin probe microscopy (SKPM). Using the electric field effect, the work function of graphene can be adjusted as the gate voltage tunes the Fermi level across the charge neutrality point. Upon biasing the device, the...
0909.0020v2
2009-09-25
A large magnetoinductance effect in La0.67Ba0.33MnO3
We report four probe impedance of La0.67Ba0.33MnO3 at f = 100 kHz under different dc bias magnetic fields. The ac resistance (R) exhibits a peak around Tp = 325 K which is accompanied by a rapid increase and a peak in the reactance (X) in a zero field. The magnetoreactance exhibits a sharp peak close to Tp and its magn...
0909.4614v1
2009-10-04
Theory of thermally activated vortex bundles flow over the directional-dependent potential barriers in type-II superocnductors
The thermally activated vortex bundle flow over the directional-dependent energy barrier in type-II superconductors is investigated. The coherent oscillation frequency and the mean direction of the random collective pinning force of the vortex bundles are evaluated by applying the random walk theorem. The thermally act...
0910.0581v3
2009-10-13
Voltage Asymmetry of Spin-Transfer Torques
We present a Non-Equilibrium Green's Function based model for spin torque transfer (STT) devices which provides quantitative agreement with experimentally measured (1) differential resistances, (2) Magnetoresistance (MR), (3) In-plane torque and (4) out-of-plane torque over a range of bias voltages, using a single set ...
0910.2489v1
2009-10-21
Low-temperature ballistic transport in nanoscale epitaxial graphene cross junctions
We report on the observation of inertial-ballistic transport in nanoscale cross junctions fabricated from epitaxial graphene grown on SiC(0001). Ballistic transport is indicated by a negative bend resistance of R12,43 ~ 170 ohm which is measured in a non-local, four-terminal configuration at 4.2 K and which vanishes as...
0910.4010v1
2009-10-24
Inducing Chalcogenide Phase Change with Ultra-Narrow Carbon Nanotube Heaters
Carbon nanotube (CNT) heaters with sub-5 nm diameter induce highly localized phase change in Ge2Sb2Te5 (GST) chalcogenide. A significant reduction in resistance of test structures is measured as the GST near the CNT heater crystallizes. Effective GST heating occurs at currents as low as 25 uA, significantly lower than ...
0910.4672v2
2009-11-09
Anomalous Nernst effect and heat transport by vortex vacancies in granular superconductors
We study the Nernst effect due to vortex motion in two-dimensional granular superconductors using simulations with Langevin or resistively shunted Josephson-junction dynamics. In particular, we show that the geometric frustration of both regular and irregular granular materials can lead to thermally driven transport of...
0911.1628v2
2010-01-19
Competing contributions of superconducting and insulating states in Ag5Pb2O6/CuO composite
The composite material, consisting of metallic particles Ag5Pb2O6 diluted in insulating CuO matrix, has been investigated in a narrow concentration range separating ballistic tunnel transport from hopping conductivity. The formation of intergrain conducting bridges between metallic particles has been avoided by a caref...
1001.3185v1
2010-01-28
Electrical observation of a tunable band gap in bilayer graphene nanoribbons at room temperature
We investigate the transport properties of double-gated bilayer graphene nanoribbons at room temperature. The devices were fabricated using conventional CMOS-compatible processes. By analyzing the dependence of the resistance at the charge neutrality point as a function of the electric field applied perpendicular to th...
1001.5213v1
2010-01-30
Magnetoresistance of a spin MOSFET with ferromagnetic MnAs source and drain contacts
Spin-dependent transport was investigated in a spin metal-oxide-semiconductor field-effect transistors (spin MOSFET) with ferromagnetic MnAs source and drain (S/D) contacts. The spin MOSFET of bottom-gate type was fabricated by photolithography using an epitaxial MnAs film grown on a silicon-on-insulator (SOI) substrat...
1002.0057v1
2010-02-03
Dislocation Mobility in a Quantum Crystal: the Case of Solid 4He
We investigate the structure and mobility of dislocations in hcp 4He crystals. In addition to fully characterizing the five elastic constants of this system, we obtain direct insight into dislocation core structures on the basal plane, which demonstrates a tendency toward dissociation into partial dislocations. Moreove...
1002.0704v1
2010-03-15
Electron localization near Mott transition in organic superconductor $κ$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}]$Br
The effect of disorder on the electronic properties near the Mott transition is studied in an organic superconductor $\kappa$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}$]Br, which is systematically irradiated by X-ray. We observe that X-ray irradiation causes Anderson-type electron localization due to molecular disorder. The resist...
1003.2890v2
2010-03-25
Columnar Fluctuations as a Source of Non-Fermi-Liquid Behavior in Weak Metallic Magnets
It is shown that columnar fluctuations, in conjunction with weak quenched disorder, lead to a T^{3/2} temperature dependence of the electrical resistivity. This is proposed as an explanation of the observed non-Fermi-liquid behavior in the helimagnet MnSi, with one possible realization of the columnar fluctuations prov...
1003.4809v3
2010-03-28
Giant magnetic broadening of ferromagnetic resonance in a GMR Co/Ag/Co/Gd quadlayer
Both magnetic-resonance damping and the giant magnetoresistance effect have been predicted to be strongly affected by the local density of states in thin ferromagnetic films. We employ the antiferromagnetic coupling between Co and Gd to provide a spontaneous change from parallel to antiparallel alignment of two Co film...
1003.5344v1
2010-04-05
Non-monotonic variation of anomalous Hall effect with spin orbit coupling strength
For L1(0) FePt films, the anomalous Hall resistivity is found to be proportional to spontaneous magnetization $M_{\mathrm{S}}$. After the $M_{\mathrm{S}}$ temperature effect is eliminated, $\rho_{\mathrm{xyo}}$ can be fitted by $\rho_{\mathrm{xyo}}=a_{\mathrm{o}}\rho_{\mathrm{xx}}+ b_{\mathrm{o}}\rho_{\mathrm{xx}}^{\ma...
1004.0548v4
2010-04-29
Designing multifunctional chemical sensors using Ni and Cu doped carbon nanotubes
We demonstrate a "bottom up" approach to the computational design of a multifunctional chemical sensor. General techniques are employed for describing the adsorption coverage and resistance properties of the sensor based on density functional theory (DFT) and non-equilibrium Green's function methodologies (NEGF), respe...
1004.5334v1
2010-05-19
Electron properties of fluorinated single-layer graphene transistors
We have fabricated transistor structures using fluorinated single-layer graphene flakes and studied their electronic properties at different temperatures. Compared with pristine graphene, fluorinated graphene has very large and strongly temperature dependent resistance in the electro-neutrality region. We show that flu...
1005.3474v3
2010-06-22
Hall carrier density and magnetoresistance measurements in thin film vanadium dioxide across the metal-insulator transition
Temperature dependent magneto-transport measurements in magnetic fields of up to 12 Tesla were performed on thin film vanadium dioxide (VO2) across the metal-insulator transition (MIT). The Hall carrier density increases by 4 orders of magnitude at the MIT and accounts almost entirely for the resistance change. The Hal...
1006.4376v1
2010-08-15
Limits on electron quality in suspended graphene due to flexural phonons
The temperature dependence of the mobility in suspended graphene samples is investigated. In clean samples, flexural phonons become the leading scattering mechanism at temperature $T \gtrsim 10\,\,$K, and the resistivity increases quadratically with $T$. Flexural phonons limit the intrinsic mobility down to a few $\tex...
1008.2522v1
2010-08-29
Shubnikov-de Haas oscillations in SrTiO3\LaAlO3 interface
Quantum magnetic oscillations in SrTiO3/\LaAlO3 interface are observed. The evolution of their frequency and amplitude at various gate voltages and temperatures is studied. The data are consistent with the Shubnikov de-Haas theory. The Hall resistivity rho exhibits nonlinearity at low magnetic field. It is fitted assum...
1008.4975v1
2010-09-01
Two distinct quasiparticle inelastic scattering rates in the $t-J$ model and their relevance for high-$T_c$ cuprates superconductors
The recent findings about two distinct quasiparticle inelastic scattering rates in angle-dependent magnetoresistance (ADMR) experiments in overdoped high-$T_c$ cuprates superconductors have motivated many discussions related to the link between superconductivity, pseudogap, and transport properties in these materials. ...
1009.0158v1
2010-10-15
Theory of I-V Characteristics of Magnetic Josephson Junctions
We analyze the electrical characteristics of a circuit consisting of a free thin-film magnetic layer and source and drain electrodes that have opposite magnetization orientations along the free magnet's two hard directions. We find that when the circuit's current exceeds a critical value there is a sudden resistance in...
1010.3073v1
2010-10-29
The Structural and Magnetic ordering in $La{}_{0.5-x}Nd_{x}Ca_{0.5}MnO_{3}$ (0.1 \ensuremath{\le} x \ensuremath{\le} 0.5) Manganites
The crystal and magnetic structure of polycrystalline $La{}_{0.5-x}Nd{}_{x}Ca_{0.5}MnO{}_{3}$ (0.0 \ensuremath{\le} x \ensuremath{\le} 0.5) samples have been investigated using magnetization, resistivity, transmission electron microscope, and neutron diffraction techniques. The samples are isostructural and possess ort...
1010.6124v1
2010-12-15
Giant Tunneling Electroresistance Effect Driven by an Electrically Controlled Spin Valve at a Complex Oxide Interface
A giant tunneling electroresistance effect may be achieved in a ferroelectric tunnel junction by exploiting the magnetoelectric effect at the interface between a ferroelectric barrier and magnetic La1-xSrxMnO3 electrode. Using first-principles density functional theory we demonstrate that a few magnetic monolayers of L...
1012.3421v2
2010-12-17
Electro thermal simulation of superconducting nanowire avalanche photodetectors
We developed an electro thermal model of NbN superconducting nanowire avalanche photodetectors (SNAPs) on sapphire substrates. SNAPs are single photon detectors consisting of the parallel connection of N superconducting nanowires. We extrapolated the physical constants of the model from experimental data and we simulat...
1012.3964v1
2010-12-17
Ternary Tetradymite Compounds as Topological Insulators
Ternary tetradymites Bi2Te2S, Bi2Te2Se and Bi2Se2Te are found to be stable, bulk topological insulators via theory, showing band inversion between group V and VI pz orbitals. We identify Bi2Se2Te as a good candidate to study massive Dirac Fermions, with a (111) cleavage-surface-derived Dirac point (DP) isolated in the ...
1012.3974v3
2011-01-18
Metal-insulator transition and electrically-driven memristive characteristics of SmNiO3 thin films
The correlated oxide SmNiO3 (SNO) exhibits an insulator to metal transition (MIT) at 130 {\deg}C in bulk form. We report on synthesis and electron transport in SNO films deposited on LaAlO3 (LAO) and Si single crystals. X-ray diffraction studies show that compressively strained single-phase SNO grows epitaxially on LAO...
1101.3538v1
2011-01-25
Ferron Type of Coductivity in Metal CuFeSe2
It is pointed out, that the charge transfer in the compound in paramagnetic region has a ferron type of transport with ferrons of a small radius, predicted by N. Mott. For some another specimen the charge transfer may be carried out by ferrons of a large radius at very low temperatures. The results are well confirmed b...
1101.4904v2
2011-02-04
Anisotropy in transport and magnetic properties of K0.64Fe1.44Se2
We report a study of anisotropy in transport and magnetic properties of K0.64Fe1.44Se2.00 single crystals. The anisotropy in resistivity is up to one order of magnitude between 1.8 K and 300 K. Magnetic susceptibility exhibits weak temperature dependence in the normal state with decrease in temperature with no signific...
1102.1010v3
2011-03-01
Experimental Spin Ratchet
Spintronics relies on the ability to transport and utilize the spin properties of an electron rather than its charge. We describe a spin rachet at the single-electron level that produces spin currents with no net bias or charge transport. Our device is based on the ground state energetics of a single electron transisto...
1103.0105v1
2011-03-15
Quantum transport in oxide nanostructures
We describe magnetotransport experiments performed on Hall crosses made from quantum wires at LaAlO3/SrTiO3 interfaces. Shubnikov-de Haas oscillations measured in a 14-nm wide structure exhibit modulations that are consistent with spin-orbit coupling or valley degeneracies. Hall measurements performed on the 6 nm-wide ...
1103.3036v1
2011-03-29
Atomistic calculation of the thermal conductance of large scale bulk-nanowire junctions
We have developed an efficient scalable kernel method for thermal transport in open systems, with which we have computed the thermal conductance of a junction between bulk silicon and silicon nanowires with diameter up to 10 nm. We have devised scaling laws for transmission and reflection spectra, which allow us to pre...
1103.5581v1
2011-03-30
Anomalous conductivity dependence of plasticized PVC for different modificator "A" concentrations and film thicknesses
The dependences of electrical conductivity of plasticized PVC films on mass fraction of plasticizer "A" and the film thickness are experimentally investigated. Non-monotonic dependence of conductivity on the concentration of plasticizer and strongly nonlinear dependence of the resistance of the film on its thickness ar...
1103.5975v1
2011-05-12
Coulomb drag in graphene single layers separated by a thin spacer
Motivated by very recent studies of Coulomb drag in grahene-BN-graphene system we develop a theory of Coulomb drag for the Fermi liquid regime, for the case when the ratio of spacer thickness $d$ to the Fermi wavelength of electrons is arbitrary. The concentration ($n$) and thickness dependence of the drag resistivity ...
1105.2534v2
2011-05-30
A ferromagnetic-like phase transition in new oxychalcogenide HgOCuSe
We report the synthesis of a new oxychalcogenide HgOCuSe sample. The resistivity decreases as a function of $T^{1.75}$ with decreasing temperature from room temperature down to around 80 K. There exists a very sharp ferromagnetic-like phase transition at around 60 K under a field of $H$ = 100 Oe. Contrary to the usual ...
1105.5868v1
2011-06-20
A fully woven touchpad sensor based on soft capacitor fibers
A novel, highly flexible capacitor fiber (with 100 nF m-1 typical capacitance per length) having a multilayer periodic structure of dielectric and conductive polymer composite films is fabricated by drawing technique. The fiber is used to build a woven touchpad sensor. Then, we study the influence of the fiber length, ...
1106.3881v1
2011-06-24
Coexistence of bulk superconductivity and charge density wave in CuxZrTe3
We report coexistence of bulk superconductivity and charge density wave (CDW) with superconducting critical temperature Tc = 3.8 K in Cu intercalated quasi-two-dimensional crystals of ZrTe3. The Cu intercalation results in the expansion of the unit cell orthogonal to the Zr-Zr metal chains (b - axis) and partial fillin...
1106.5047v1
2011-08-01
Enhancement of Spin Injection into Graphene by Water Dipping
We immerse single layer graphene spin valves into purified water for a short duration (<1 min) and investigate the effect on spin transport. Following water immersion, we observe an enhancement in nonlocal magnetoresistance. Additionally, the enhancement of spin signal is correlated with an increase in junction resista...
1108.0380v1
2011-08-12
Magnetic noise induced by dc current in a micron-size magnetic wire
The magnetic noise spectra induced by direct-current (dc) current flowing through a micron-scale ferromagnetic wire have been investigated. We have observed the noise spectra with a resonance frequency. Under the application of the magnetic field in the plane, the magnetic field dependences of the resonance frequency a...
1108.2548v1
2011-09-29
Sources of negative tunneling magneto-resistance in multilevel quantum dots with ferromagnetic contacts
We analyze distinct sources of spin-dependent energy level shifts and their impact on the tunneling magnetoresistance (TMR) of interacting quantum dots coupled to collinearly polarized ferromagnetic leads. Level shifts due to virtual charge fluctuations can be quantitatively evaluated within a diagrammatic representati...
1109.6599v1
2011-10-13
Tuning the structural instability of SrTiO_3 by Eu doping: The phase diagram of Sr_1-xEu_xTiO_3
The phase diagram of Sr_1-xEu_xTiO_3 is determined experimentally by electron paramagnetic resonance and resistivity measurements and analyzed theoretically within the self-consistent phonon approximation as a function of x ([0.03-1.0]). The transition temperature of the structural instability of the system increases n...
1110.2922v2
2011-11-21
Ink-Jet Printed Graphene Electronics
We demonstrate ink-jet printing as a viable method for large area fabrication of graphene devices. We produce a graphene-based ink by liquid phase exfoliation of graphite in N-Methylpyrrolidone. We use it to print thin-film transistors, with mobilities up to~95cm^2V^(-1)s(-1), as well as transparent and conductive patt...
1111.4970v1
2011-11-24
Domain wall attraction and repulsion during spin-torque-induced coherent motion
We calculate the interaction between two magnetic domain walls during their current-induced motion. This interaction produces a separation-dependent resistance and also a differential velocity, causing domains in motion to experience an effective attraction at large separations and an effective repulsion at short separ...
1111.5868v1
2011-12-09
Characterization and Predictive Modeling of Epitaxial Silicon-Germanium Thermistor Layers
The thermal coefficient of resistance (TCR) for epitaxial silicon-germanium (SiGe) layers has been analyzed by experiment and simulation. Predictive simulation using drift-diffusion formalism and self-consistent quantum-mechanical solutions yielded similar results, TCR around 2%/K at 300 K. This modeling approach can b...
1112.2043v1
2011-12-14
Possibility of a zero-temperature metallic phase in granular two-band superconducting films
A variational approach is used to study the superconductor-insulator transition in two-band granular superconducting films using a resistance-shunted Josephson junction array model in this letter. We show that a zero-temperature metallic phase may exist between the superconducting and insulator phases which is absent i...
1112.3132v2
2012-02-08
Seismic Waveguide of Metamaterials
We have developed a new method of an earthquake-resistant design to support conventional aseismic designs using acoustic metamaterials. We suggest a simple and practical method to reduce the amplitude of a seismic wave exponentially. Our device is an attenuator of a seismic wave. Constructing a cylindrical shell-type w...
1202.1586v1
2012-04-10
Modeling the underlying mechanisms for organic memory devices: Tunneling, electron emission and oxygen adsorbing
We present a combined experimental and theoretical study to get insight into both memory and negative differential resistance (NDR) effect in organic memory devices. The theoretical model we propose is simply a one-dimensional metallic island array embedding within two electrodes. We use scattering operator method to e...
1204.2022v1
2012-04-18
Magnetoresistance Relaxation in (La0.5Eu0.5)0.7Pb0.3MnO3 Single Crystals under the Action of a Pulse Magnetic Field
Magnetoresistance of substituted lanthanum manganite (La0.5Eu0.5)0.7Pb0.3MnO3 in the pulse magnetic field H = 25 T was measured at different temperatures. Magnetoresistance relaxation with a characteristic time of 10 -3 s was found. It has been established that the temperature dependence of the relaxation parameter {\t...
1204.3987v1
2012-05-18
Metal-to-insulator transition in anatase TiO2 thin films induced by growth rate modulation
We demonstrate control of the carrier density of single phase anatase TiO2 thin films by nearly two orders of magnitude by modulating the growth kinetics during pulsed laser deposition, under fixed thermodynamic conditions. The resistivity and the intensity of the photoluminescence spectra of these TiO2 samples, both o...
1205.4065v1
2012-05-30
Type-I superconductivity in ScGa3 and LuGa3 single crystals
We present evidence of type-I superconductivity in single crystals of ScGa3 and LuGa3, from magnetization, specific heat, and resistivity measurements: low critical temperatures Tc = 2.1-2.2 K; field-induced secondto first-order phase transition in the specific heat, critical fields less than 240 Oe; and low Ginzburg-L...
1205.6836v1
2012-07-20
Superconducting state in the metastable binary bismuthide Rh3Bi14 single crystals
We report detailed magnetic, transport and thermodynamic properties of metastable Rh3Bi14 single crystals in superconducting and normal state. We show that Rh3Bi14 is nearly isotropic, weak to intermediately coupled BCS superconductor, whereas the electronic resistivity above superconducting Tc = 2.94 K is dominated by...
1207.5043v1
2012-08-23
Evolution of c-f hybridization and two component Hall effect in β-YbAlB_4
\beta-YbAlB_4 is the unique heavy fermion superconductor that exhibits unconventional quantum criticality without tuning in a strongly intermediate valence state. Despite the large coherence temperature, set by the peak of the longitudinal resistivity, our Hall effect measurements reveal that resonant skew scattering f...
1208.4680v1
2012-08-28
Trench Gate Power MOSFET: Recent Advances and Innovations
The trench gate MOSFET has established itself as the most suitable power device for low to medium power applications by offering the lowest possible ON resistance among all MOS devices. The evolution of the trench gate power MOSFET has been discussed in this chapter, starting right from its beginnings to the recent tre...
1208.5553v1