publicationDate
stringlengths
10
10
title
stringlengths
17
233
abstract
stringlengths
20
3.22k
id
stringlengths
9
12
2002-07-05
On the two-dimensional metallic state in silicon-on-insulator structures
It is shown that the electronic conduction in silicon-on-insulator (SOI) layers exhibits a metallic regime which is very similar to that in high-mobility Si-metal oxide semiconductor structures (MOS). The peak in the electron mobility versus density, the strong drop in resistivity and the critical concentration for the...
0207170v1
2003-01-21
Angular dependence of domain wall resistivity in SrRuO$_{\bf 3}$ films
${\rm SrRuO_3}$ is a 4d itinerant ferromagnet (T$_{c}$ $\sim $150 K) with stripe domain structure. Using high-quality thin films of SrRuO$_{3}$ we study the resistivity induced by its very narrow ($\sim 3$ nm) Bloch domain walls, $\rho_{DW}$ (DWR), at temperatures between 2 K and T$_{c}$ as a function of the angle, $\t...
0301400v2
2003-04-30
Radiation-induced magnetoresistance oscillation in a two-dimensional electron gas in Faraday geometry
Microwave-radiation induced giant magnetoresistance oscillations recently discovered in high-mobility two-dimensional electron systems in a magnetic field, are analyzed theoretically. Multiphoton-assisted impurity scatterings are shown to be the primary origin of the oscillation. Based on a model which considers the in...
0304687v2
2003-06-03
Signatures of valence fluctuations in CeCu2Si2 under high pressure
Simultaneous resistivity and a.c.-specific heat measurements have been performed under pressure on single crystalline CeCu2Si2 to over 6 GPa in a hydrostatic helium pressure medium. A series of anomalies were observed around the pressure coinciding with a maximum in the superconducting critical temperature, $T_c^{max}$...
0306054v1
2003-06-09
Thermal fluctuations in ultrasmall intrinsic Josephson junctions
Current-voltage curves of small area hysteretic intrinsic Josephson junctions, for which the Josephson energy $E_J=\hbar J_c/2e$ is of order of thermal energy $kT$, are investigated. A non-monotonic temperature dependence of the switching current is observed and explained by thermal phase fluctuations. At low temperatu...
0306212v1
2003-11-25
Comparative study of in situ and ex situ MgB2 films deposited by pulsed laser deposition
Two types of MgB2 films were prepared by pulsed laser deposition (PLD) with in situ and ex situ annealing processes respectively. Significant differences in properties between the two types of films were found. The ex situ MgB2 film has a Tc of 38.1K, while the in situ film has a depressed Tc of 34.5K. The resistivity ...
0311556v1
2004-02-12
Self-localization of holes in a lightly doped Mott insulator
We show that lightly doped holes will be self-trapped in an antiferromagnetic spin background at low-temperatures, resulting in a spontaneous translational symmetry breaking. The underlying Mott physics is responsible for such novel self-localization of charge carriers. Interesting transport and dielectric properties a...
0402327v2
2004-03-09
Resistivity and Thermopower of Ni2.19Mn0.81Ga
In this paper, we report results of the first studies on the thermoelectric power (TEP) of the magnetic heusler alloy Ni$_{2.19}$Mn$_{0.81}$Ga. We explain the observed temperature dependence of the TEP in terms of the crystal field (CF) splitting and compare the observed behavior to that of the stoichiometric system Ni...
0403232v2
2004-07-21
YbNiSi3: a new antiferromagnetic Kondo lattice with strong exchange interaction
We report on the structural, thermodynamic and transport properties of high-quality single crystals of YbNiSi3 grown by the flux method. This compound crystallizes in the SmNiGe3 layered structure type of the Cmmm space group. The general physical behavior is that of a Kondo lattice showing an antiferromagnetic ground ...
0407543v1
2004-09-05
Infrared study of giant dielectric constant in Li and Ti doped NiO
We have measured optical reflectivity of Li and Ti doped NiO (LTNO) in the infrared range at various temperatures. A Drude-like absorption is found at low energy, $\omega <$ 100 cm$^{-1}$ and its spectral weight increases substantially as temperature decreases. This observation and DC-resistivity result show that LTNO ...
0409105v1
2004-09-09
Anomalous Pressure Dependence of Kadowaki-Woods ratio and Crystal Field Effects in Mixed-valence YbInCu4
The mixed-valence (MV) compound YbInCu4 was investigated by electrical resistivity and ac specific heat at low temperatures and high pressures. At atmospheric pressure, its Kadowaki-Woods (KW) ratio, A/\gamma ^2, is 16 times smaller than the universal value R_{KW}(=1.0 x 10^-5 \mu \Omega cm mol^2 K^2 mJ^-2), but sharpl...
0409243v2
2004-10-01
Inherent Relation between Nernst Signal and Nodal Quasiparticle Transport in Pseudogap Region of Underdoped High Temperature Superconductors
In-plane Nernst signal and resistivity have been measured for three $La_{2-x}Sr_xCuO_4$ single crystals (x=0.09, 0.11 and 0.145) with the magnetic field parallel to c-axis. A quadratic temperature dependence of resistivity, i.e., $\rho=\rho_0+aT^2$ is observed below a certain temperature $T_R$. It is found that the upp...
0410013v2
2004-11-23
Magnetic field-tuned quantum critical point in CeAuSb_2
Transport, magnetic and thermal properties at high magnetic fields (H) and low temperatures (T) of the heavy fermion compound CeAuSb_2 are reported. At H=0 this layered system exhibits antiferromagnetic order below T_N = 6 K. Applying B along the inter-plane direction, leads to a continuous suppression of T_N and a qua...
0411588v2
2005-02-14
Superconductivity induced by spark erosion in ZrZn2
We show that the superconductivity observed recently in the weak itinerant ferromagnet ZrZn2 [C. Pfleiderer et al., Nature (London) 412, 58 (2001)] is due to remnants of a superconducting layer induced by spark erosion. Results of resistivity, susceptibility, specific heat and surface analysis measurements on high-qual...
0502341v2
2005-04-05
Interaction and disorder in bilayer counterflow transport at filling factor one
We study high mobility, interacting GaAs bilayer hole systems exhibiting counterflow superfluid transport at total filling factor $\nu=1$. As the density of the two layers is reduced, making the bilayer more interacting, the counterflow Hall resistivity ($\rho_{xy}$) decreases at a given temperature, while the counterf...
0504119v1
2005-05-19
On the problem of the Kondo-lattice model application to CeB6
Precision measurements of charge transport parameters (resistivity, Hall and Seebeck coefficients) have been carried out on high-quality single-crystals of cerium hexaboride in a wide temperature range 1.8-300 K. It is shown that in the temperature interval of 5 K < T < T* = 80 K the magnetic contribution in resistivit...
0505475v1
2005-06-15
Resistivity study of the pseudogap phase for (Hg,Re) - 1223 superconductors
The pseudogap phase above the critical temperature of high $T_{c}$ superconductors (HTSC) presents different energy scales and it is currently a matter of intense study. The complexity of the HTSC normal state requires very accurate measurements with the purpose of distinguishing different types of phenomena. Here we h...
0506387v2
2005-08-29
Universal Minimum Heat Leak on Low-Temperature Metallic Electrical Leads
Low-temperature electronic systems require electrical leads which have low electrical resistance to provide bias current I without excessive voltage drop V. But proper cryogenic design also requires high thermal resistance to maintain a minimum heat leak Q from the hot temperature T[hot] to the cold temperature T[cold]...
0508697v2
2005-09-01
Comment on "Magnetic quantum oscillations of the conductivity in layered conductors"
We discuss the recent theory of Gvozdikov [Phys. Rev. B 70, 085113 (2004)] which aims at explaining the Shubnikov-de Haas oscillations of the longitudinal resistivity \rho_zz observed in the quasi-two-dimensional organic compound \beta''-(BEDT-TTF)_2SF_5CH_2CF_2SO_3. We point out that the self-consistent equations of...
0509026v2
2005-10-14
Ferromagnetic Properties of ZrZn$_2$
The low Curie temperature (T_C approx 28K) and small ordered moment (M_0 approx 0.17 mu_B f.u.^-1) of ZrZn2 make it one of the few examples of a weak itinerant ferromagnet. We report results of susceptibility, magnetization, resistivity and specific heat measurements made on high-quality single crystals of ZrZn2. From ...
0510384v1
2005-12-23
Spin-charge gauge symmetry: A way to tackle HTS cuprates?
We propose an explanation of several experimental features of transport phenomena in the normal state of high Tc cuprates in terms of a spin-charge gauge theory of the 2D t-J model. The calculated doping-temperature dependence for a number of physical quantities is found in qualitative agreement with data. In particula...
0512607v1
2006-02-01
Coulomb blockade and transport in a chain of one-dimensional quantum dots
A long one-dimensional wire with a finite density of strong random impurities is modelled as a chain of weakly coupled quantum dots. At low temperature T and applied voltage V its resistance is limited by "breaks": randomly occuring clusters of quantum dots with a special length distribution pattern that inhibits the t...
0602008v3
2006-02-14
Intrinsic nonlinearity probed by intermodulation distortion microwave measurements on high quality MgB2 thin films
The two tone intermodulation distortion arising in MgB2 thin films synthesized by hybrid physical-chemical vapour deposition is studied in order to probe the influence of the two bands on the nonlinear response of this superconductor. The measurements are carried out by using a dielectrically loaded copper cavity opera...
0602340v1
2006-02-21
Evidence of s-wave pairing symmetry in layered superconductor Li$_{0.68}$NbO$_2$ from the specific heat measurement
A high quality superconducting Li$_{0.68}$NbO$_2$ polycrystalline sample was synthesized by deintercalation of Li ions from Li$_{0.93}$NbO$_2$. The field dependent resistivity and specific heat were measured down to 0.5 K. The upper critical field $H_{c2} (T)$ is deduced from the resistivity data and $H_{c2}(0)$ is est...
0602476v1
2006-03-29
Resistivity and Magneto-Optical Evidence for Variable and Incomplete Connectivity in Dense, High Critical Current Density C-alloyed Magnesium Diboride
Carbon-doped magnesium diboride was fabricated from pre-reacted pure MgB2 by mechanical alloying. The sample set had excellent critical current densities Jc(8T,4.2K) ranging from 15-60 kA/cm2, depending on composition. Magneto-optical imaging detected regions up to 0.5 mm in size which were nearly 100% dense with Jc 2-...
0603800v1
2006-06-08
Periodic Oscillations of Josephson-Vortex Flow Resistance in Oxygen-Deficient Y1Ba2Cu3Ox
We measured the Josephson vortex flow resistance as a function of magnetic field applied parallel to the ab-planes using annealed Y1Ba2Cu3Ox intrinsic Josephson junctions having high anisotropy (around 40) by oxygen content reduction. Periodic oscillations were observed in magnetic fields above 45-58 kOe, corresponding...
0606202v2
2006-06-26
Flux-flow resistivity anisotropy in the instability regime in the a-b plane of epitaxial YBCO thin films
Measurements of the nonlinear flux-flow resistivity $\rho$ and the critical vortex velocity $\rm v^*_\phi$ at high voltage bias close to the instability regime predicted by Larkin and Ovchinnikov \cite{LO} are reported along the node and antinode directions of the d-wave order parameter in the \textit{a-b} plane of epi...
0606667v1
2006-07-01
Nonlocal Effect of Local Nonmagnetic Impurity in High-Tc Superconductors: Induced Local Moment and Huge Residual Resistivity
We study a Hubbard model with a strong onsite impurity potential based on an improved fluctuation-exchange (FLEX) approximation, which we call the GVI-FLEX method. We find that (i) both local and staggered susceptibilities are strongly enhanced around the impurity. By this reason, (ii) the quasiparticle lifetime as wel...
0607011v1
2006-07-21
Vortex state microwave resistivity in Tl-2212 thin films
We present measurements of the field induced changes in the 47 GHz complex resistivity, $\Delta \tilde \rho(H,T)$, in Tl$_{2}$Ba$_{2}$CaCu$_{2}$O$_{8+x}$ (TBCCO) thin films with $T_{c}\simeq$ 105 K, prepared on CeO$_{2}$ buffered sapphire substrates. At low fields ($\mu_{0}H<$10 mT) a very small irreversible feature is...
0607552v1
2006-08-31
Magnetotransport in a two-dimensional electron system in dc electric fields
We report on nonequilibrium transport measurements in a high-mobility two-dimensional electron system subject to weak magnetic field and dc excitation. Detailed study of dc-induced magneto-oscillations, first observed by Yang {\em et al}., reveals a resonant condition that is qualitatively different from that reported ...
0608727v3
2006-10-04
Quantum phase transition in the heavy-fermion compound YbIr$_2$Si$_2$
We investigate the pressure-temperature phase diagram of YbIr$_2$Si$_2$ by measuring the electrical resistivity $\rho(T)$. In contrast to the widely investigated YbRh$_2$Si$_2$, YbIr$_2$Si$_2$ is a paramagnetic metal below $p_c\simeq 8$ GPa. Interestingly, a first-order, presumably ferromagnetic, transition develops at...
0610126v1
2006-11-09
Small-angle interband scattering as the origin of the $T^{3/2}$ resistivity in MnSi
A possible explanation is given for the anomalous $T^{3/2}$ temperature dependence of the electrical resistivity of MnSi, which is observed in the high-pressure paramagnetic state. The unusual Fermi surface of MnSi includes large open sheets that intersect along the faces of the cubic Brillouin zone. Close to these int...
0611236v1
2006-12-22
Transport through normal metal - graphene contacts
Conductance of zigzag interfaces between graphene sheet and normal metal is investigated in the tight-binding approximation. Boundary conditions, valid for a variety of scattering problems, are constructed and applied to the normal metal -- graphene -- normal metal (NGN) junctions. At the Dirac point, the conductance i...
0612577v3
2007-01-04
Anomalous Hall Resistance in Bilayer Quantum Hall Systems
We present a microscopic theory of the Hall current in the bilayer quantum Hall system on the basis of noncommutative geometry. By analyzing the Heisenberg equation of motion and the continuity equation of charge, we demonstrate the emergence of the phase current in a system where the interlayer phase coherence develop...
0701063v1
1995-12-08
The Complex Structure of 2D Surfaces
The complex structure of a surface generated by the two-dimensional dynamical triangulation(DT) is determined by measuring the resistivity of the surface. It is found that surfaces coupled to matter fields have well-defined complex structures for cases when the matter central charges are less than or equal to one, whil...
9512014v1
2006-08-07
Random walk on the incipient infinite cluster for oriented percolation in high dimensions
We consider simple random walk on the incipient infinite cluster for the spread-out model of oriented percolation on $Z^d \times Z_+$. In dimensions $d>6$, we obtain bounds on exit times, transition probabilities, and the range of the random walk, which establish that the spectral dimension of the incipient infinite cl...
0608164v2
2003-02-21
New results from an extensive aging test on bakelite Resistive Plate Chambers
We present recent results of an extensive aging test, performed at the CERN Gamma Irradiation Facility on two single--gap RPC prototypes, developed for the LHCb Muon System. With a method based on a model describing the behaviour of an RPC under high particle flux conditions, we have periodically measured the electrode...
0302077v2
2004-03-09
Measuring the force ejecting DNA from phage
We discuss how a balance can be established between the force acting to eject DNA from viral capsids and the force resisting its entry into a colloidal suspension which mimics the host cell cytoplasm. The ejection force arises from the energy stored in the capsid as a consequence of the viral genome (double-stranded DN...
0403057v1
2006-08-04
Design guide for electronics for resistive charge division in thermal neutron detection
An amplifier has been designed for optimal use of position sensitive thermal neutron detectors using the principle of resistive charge division. The important points in this optimization are: high counting rates and good spatial resolution. This amplifier is built as a hybrid circuit and is now used on several new inst...
0608046v1
2002-05-20
A Zoology of Bell inequalities resistant to detector inefficiency
We derive both numerically and analytically Bell inequalities and quantum measurements that present enhanced resistance to detector inefficiency. In particular we describe several Bell inequalities which appear to be optimal with respect to inefficient detectors for small dimensionality d=2,3,4 and 2 or more measuremen...
0205130v2
2007-05-17
Incoherent non-Fermi liquid scattering in a Kondo lattice
One of the most notorious non-Fermi liquid properties of both archetypal heavy-fermion systems [1-4] and the high-Tc copper oxide superconductors [5] is an electrical resistivity that evolves linearly with temperature, T. In the heavy-fermion superconductor CeCoIn5 [5], this linear behaviour was one of the first indica...
0705.2592v2
2007-07-22
Investigations of a THGEM-based imaging detector
We present the results of our recent studies on a Thick Gas Electron Multiplier (THGEM)-based imaging detector prototype. It consists of two 100x100 mm^2 THGEM electrodes in cascade, coupled to a resistive anode. The event location is recorded with a 2D double-sided readout electrode equipped with discrete delay-lines ...
0707.3257v3
2007-08-13
Optimized minigaps for negative differential resistance creation in strongly delta-doped (1D) superlattices
The "atomic saw method" uses the passage of dislocations in two-dimensional (2D) quantum-well superlattices to create periodic slipping layers and one-dimensional (1D) quantum wire superlattices. The effects of this space structuring of the samples on the allowed energies are analysed in the case of GaAs d-doped superl...
0708.1673v1
2007-09-13
Influence of Mg Deficiency on the Superconductivity in MgB2 Thin Films Grown by using HPCVD
The effects of Mg deficiency in MgB2 films grown by using hybrid physical-chemical vapor deposition were investigated after vacuum annealing at various temperatures. High-quality MgB2 films grown on c-cut Al2O3 substrates with different superconducting transition temperatures (Tc) of 40.2 and 41 K were used in this stu...
0709.1989v1
2007-12-20
The evolution of the Non-Fermi Liquid behavior of BaVS$_3$ under high pressure
Temperature, pressure, and magnetic field dependencies of the resistivity of BaVS$_3$ were measured above the critical pressure of $p_{cr}$=2 GPa, which is associated with the zero temperature insulator-to-metal (MI) transition. The resistivity exhibits the $T^n$ temperature dependence below $T_g\approx$15 K, with $n$ ...
0712.3393v1
2008-02-05
Verwey transition in Fe$_{3}$O$_{4}$ at high pressure: quantum critical behavior at the onset of metallization
We provide evidence for the existence of a {\em quantum critical point} at the metallization of magnetite Fe$_{3}$O$_{4}$ at an applied pressure of $p_{c} \approx 8$ GPa. We show that the present ac magnetic susceptibility data support earlier resistivity data. The Verwey temperature scales with pressure $T_{V}\sim (1-...
0802.0631v1
2008-02-20
Development of bakelite based Resistive Plate Chambers
A Comparative study has been performed on Resistive Plate Chambers made of different grades of bakelite paper laminates, produced and commercially available in India. The chambers, operated in the streamer mode using argon : tetrafluroethane : isobutane in 34:59:7 mixing ratio, are tested with cosmic rays for the effic...
0802.2766v1
2008-03-06
Graph Sparsification by Effective Resistances
We present a nearly-linear time algorithm that produces high-quality sparsifiers of weighted graphs. Given as input a weighted graph $G=(V,E,w)$ and a parameter $\epsilon>0$, we produce a weighted subgraph $H=(V,\tilde{E},\tilde{w})$ of $G$ such that $|\tilde{E}|=O(n\log n/\epsilon^2)$ and for all vectors $x\in\R^V$ $(...
0803.0929v4
2008-03-12
Bardeen-Stephen flux flow law disobeyed in the high-$T_c$ superconductor Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+δ}$
Pulsed high current experiments in single crystals of the high-$T_{c}$ superconductor Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ in c-axis directed magnetic field $H$ reveal that the $ab$-face resistance in the free flux flow regime is a solely logarithmic function of H, devoid of any power law component. Re-analysis of ...
0803.1804v1
2008-05-05
Fast dynamos in weakly ionized gases
The turnover of interstellar gas on $\sim 10^9$yr timescales argues for the continuous operation of a galactic dynamo. The conductivity of interstellar gas is so high that the dynamo must be "fast" - i.e. the magnetic field must be amplified at a rate nearly independent of the magnetic diffusivity. Yet, all the fast dy...
0805.0412v1
2008-05-26
Negative differential resistance in molecular junctions: application to graphene ribbon junctions
Using self-consistent calculations based on Non-Equilibrium Green's Function (NEGF) formalism, the origin of negative differential resistance (NDR) in molecular junctions and quantum wires is investigated. Coupling of the molecule to electrodes becomes asymmetric at high bias due to asymmetry between its highest occupi...
0805.3980v1
2008-06-10
Are Microwave Induced Zero Resistance States Necessarily Static?
We study the effect of inhomogeneities in Hall conductivity on the nature of the Zero Resistance States seen in the microwave irradiated two-dimensional electron systems in weak perpendicular magnetic fields, and we show that time-dependent domain patterns may emerge in some situations. For an annular Corbino geometry,...
0806.1562v1
2008-06-13
Synthesis, crystal structure, microstructure, transport and magnetic properties of SmFeAsO and SmFeAs(O0.93F0.07)
SmFeAsO and the isostructural superconducting SmFeAs(O0.93F0.07) samples were prepared. Characterization by means of Rietveld refinement of X-ray powder diffraction data, scanning electron microscope observation, transmission electron microscope analysis, resistivity and magnetization measurements were carried out. Sin...
0806.2205v1
2008-07-17
Photosensitive Strip RETHGEM
An innovative photosensitive gaseous detector, consisting of a GEM like amplification structure with double layered electrodes (instead of commonly used metallic ones) coated with a CsI reflective photocathode, is described. In one of our latest designs, the inner electrode consists of a metallic grid and the outer one...
0807.2718v1
2008-07-21
Superconductivity at 34.7 K in the iron arsenide Eu0.7Na0.3Fe2As2
EuFe2As2 is a member of the ternary iron arsenide family. Similar to BaFe2As2 and SrFe2As2, EuFe2As2 exhibits a clear anomaly in resistivity near 200 K. It suggests that EuFe2As2 is another promising parent compound in which superconductivity may be realized by appropriate doping. Here we report the discovery of superc...
0807.3293v3
2008-08-03
Magnetic and Transport Studies on Electron-doped CeFeAsO1-xFx Superconductor
The magnetic and transport behaviors of cerium substituted iron oxy-arsenide superconductor with x = 0.1 to 0.4 fluoride (F) doping have been investigated in this report. Temperature dependent susceptibility and resistivity measurements showed the 0.1 F-doped sample (CeFeAsO0.9F0.1) has a superconducting transition tem...
0808.0296v1
2008-08-22
Correlation between extrinsic electroresistance and magnetoresistance in fine-grained La0.7Ca0.3MnO3
We report our observation of a correlation between the extrinsic electroresistance (EER) and magnetoresistance (EMR) via grain size in fine-grained La0.7Ca0.3MnO3. The nature of dependence of EER and EMR on grain size (~0.2-1.0 micron) indicates that for finer grains with low-resistive boundaries both of them follow si...
0808.3043v2
2008-09-28
Scaling of 1/f noise in tunable break-junctions
We have studied the $1/f$ voltage noise of gold nano-contacts in electromigrated and mechanically controlled break-junctions having resistance values $R$ that can be tuned from 10 $\Omega$ (many channels) to 10 k$\Omega$ (single atom contact). The noise is caused by resistance fluctuations as evidenced by the $S_V\prop...
0809.4841v1
2008-10-20
Polaron relaxation and hopping conductivity in LaMn$_{1-x}$Fe$_{x}$O$_3$
Dc and ac transport properties as well as electric modulus spectra have been investigated for the samples LaMn$_{1-x}$Fe$_{x}$O$_3$ with compositions 0 $\leq x \leq$ 1.0. The bulk dc resistivity shows a temperature variation consistent with the variable range hopping mechanism at low temperature and Arrhenius mechanism...
0810.3502v1
2008-11-05
Superconductivity at 56 K in Samarium-doped SrFeAsF
We synthesized the samples Sr$_{1-x}$Sm$_x$FFeAs with ZrCuSiAs-type structure. These samples were characterized by resistivity and susceptibility. It is found that substitution of rare earth metal for alkaline earth metal in this system suppresses the anomaly in resistivity and induces superconductivity. Superconductiv...
0811.0761v3
2008-12-31
Cosmic-ray driven dynamo in galactic disks
We present new developments on the Cosmic--Ray driven, galactic dynamo, modeled by means of direct, resistive CR--MHD simulations, performed with ZEUS and PIERNIK codes. The dynamo action, leading to the amplification of large--scale galactic magnetic fields on galactic rotation timescales, appears as a result of galac...
0901.0111v1
2009-01-13
Spin-Orbit Scattering and Quantum Metallicity in Ultra-Thin Be Films
We compare and contrast the low temperature magnetotransport properties of ultra-thin, insulating, Be films with and without spin-orbit scattering (SOS). Beryllium films have very little intrinsic SOS, but by "dusting" them with sub-monolayer coverages of Au, one can introduce a well controlled SOS rate. Pure Be films ...
0901.1873v1
2009-02-12
Two-Fluid Magnetohydrodynamic Simulations of Relativistic Magnetic Reconnection
We investigate the large scale evolution of a relativistic magnetic reconnection in an electron-positron pair plasma by a relativistic two-fluid magnetohydrodynamic (MHD) code. We introduce an inter-species friction force as an effective resistivity to dissipate magnetic fields. We demonstrate that magnetic reconnectio...
0902.2074v2
2009-03-03
Insulating Phases Induced by Crossing of Partially Filled Landau Levels in a Si Quantum Well
We study magnetotransport in a high mobility Si two-dimensional electron system by in situ tilting of the sample relative to the magnetic field. A pronounced dip in the longitudinal resistivity is observed during the Landau level crossing process for noninteger filling factors. Together with a Hall resistivity change w...
0903.0486v2
2009-03-22
The Turbulent Magnetic Prandtl Number of MHD Turbulence in Disks
The magnetic Prandtl number Pr_M is the ratio of viscosity to resistivity. In astrophysical disks the diffusion of angular momentum (viscosity) and magnetic fields (resistivity) are controlled by turbulence. Phenomenological models of the evolution of large scale poloidal magnetic fields in disks suggest that the turbu...
0903.3757v1
2009-04-08
Gate-controlled non-volatile graphene-ferroelectric memory
In this letter, we demonstrate a non-volatile memory device in a graphene FET structure using ferroelectric gating. The binary information, i.e. "1" and "0", is represented by the high and low resistance states of the graphene working channels and is switched by controlling the polarization of the ferroelectric thin fi...
0904.1326v2
2009-04-13
Breakdown of the N=0 Quantum Hall State in graphene: two insulating regimes
We studied the unusual Quantum Hall Effect (QHE) near the charge neutrality point (CNP) in high-mobility graphene sample for magnetic fields up to 18 T. We observe breakdown of the delocalized QHE transport and strong increase in resistivities $\rho_{xx},|\rho_{xy}|$ with decreasing Landau level filling for $\nu < 2$, ...
0904.1996v3
2009-08-03
The role of thermal conduction in magnetized viscous-resistive ADAFs
Observations of the hot gas, which is surrounding Sgr A* and a few other nearby galactic nuclei, imply that mean free paths of electron and proton are comparable to gas capture radius. So, hot accretion flows likely proceed under week collision conditions. As a result thermal conduction by ions has a considerable contr...
0908.0325v1
2009-08-23
Direct Measurement of Thermal Fluctuation of High-Q Pendulum
We achieved for the first time a direct measurement of the thermal fluctuation of a pendulum in an off-resonant region using a laser interferometric gravitational wave detector. These measurements have been well identified for over one decade by an agreement with a theoretical prediction, which was derived by a fluctua...
0908.3227v1
2009-08-25
Superconductivity in a single C60 transistor
Single molecule transistors (SMTs) are currently attracting enormous attention as possible quantum information processing devices. An intrinsic limitation to the prospects of these however is associated to the presence of a small number of quantized conductance channels, each channel having a high access resistance of ...
0908.3638v1
2009-08-26
Observation of quantum-Hall effect in gated epitaxial graphene grown on SiC (0001)
Epitaxial graphene films were formed on the Si-face of semi-insulating 4H-SiC substrates by a high temperature sublimation process. A high-k gate stack on epitaxial graphene is realized by inserting a fully oxidized nanometer thin aluminum film as a seeding layer followed by an atomic-layer deposition process. The elec...
0908.3822v3
2009-12-03
C-axis critical current of a PrFeAsO0.7 single crystal
The c-axis transport properties of a high-pressure synthesized PrFeAsO0.7 single crystal are studied using s-shaped junctions. Resistivity anisotropy of about 120 detected at 50 K shows the presence of strong anisotropy in the electronic states. The obtained critical current density for the c-axis of 2.9*10^5 A/cm^2 is...
0912.0598v1
2010-01-12
Resistive Magnetic Field Generation at Cosmic Dawn
Relativistic charged particles (CR for cosmic-rays) produced by Supernova explosion of the first generation of massive stars that are responsible for the re-ionization of the universe escape into the intergalactic medium, carrying an electric current. Charge imbalance and induction give rise to a return current, $\vec ...
1001.2011v2
2010-01-19
Theory of Normal State Pseudogap Behavior in FeSe(1-x)$Te(x)
The normal state of the recently discovered Iron Selenide (FeSe)-based superconductors shows a range of inexplicable features. Along with bad-metallic resistivity, characteristic pseudogap features and proximity to insulating states, reminiscent of the underdoped high-Tc cuprates, mark these systems as strongly correla...
1001.3273v1
2010-02-08
Indirect Magnetic-Field-Tuned Superconductor-Insulator Transitions and Weak Localization of Bosons of Quasi-Two Dimensional Metal Films
Magnetic field and electrostatically tuned superconductor-insulator (SI) transitions of ultrathin metal films with levels of disorder that place them near the disorder-tuned SI transition appear to be direct, continuous quantum phase transitions. When films with lower levels of disorder are subjected to a perpendicular...
1002.1720v1
2010-02-16
Dynamic Nuclear Polarization and Nuclear Magnetic Resonance in the Simplest Pseudospin Quantum Hall Ferromagnet
We present dynamic nuclear polarization (DNP) in the simplest pseudospin quantum Hall ferromagnet (QHF) of an InSb two-dimensional electron gas with a large g factor using tilted magnetic fields. The DNP-induced amplitude change of a resistance spike of the QHF at large current enables observation of the resistively de...
1002.3087v3
2010-02-28
Microwave-induced magnetoresistance of two-dimensional electrons interacting with acoustic phonons
The influence of electron-phonon interaction on magnetotransport in two-dimensional electron systems under microwave irradiation is studied theoretically. Apart from the phonon-induced resistance oscillations which exist in the absence of microwaves, the magnetoresistance of irradiated samples contains oscillating cont...
1003.0178v1
2010-03-19
Evidence for Anisotropic Vortex Dynamics and Pauli Limitation in the Upper Critical Field of FeSe1-xTex
We have determined HC2(T) for FeSe1-xTex (x=0.52) single crystals using resistivity measurements at high static and pulsed magnetic field, as well as specific heat measurements up to 9T. We find that the significant anisotropy of the initial slope of HC2(T) determined from resistivity measurements, is not present when ...
1003.3812v1
2010-03-29
Three Dimensional Superconductivity in FeSe with Tczero Up to 10.9 K Induced by Internal Strain
Polycrystalline sample FeSe was synthesized by a self-flux solution method which shows a zero resistance temperature up to 10.9 K and a Tconset (90% \rhon, \rhon: normal state resistivity) up to 13.3 K. The decrease of superconducting transition temperature by heat treatment indicates that internal crystallographic str...
1003.5415v1
2010-06-01
Synthesis, structural and physical properties of $δ'$-FeSe$_{1-x}$
We report on synthesis, structural characterization, resistivity, magnetic and thermal expansion measurements on the as yet unexplored $\delta'$-phase of FeSe$_{1-x}$, here synthesized under ambient- (AP) and high-pressure (HP) conditions. We show that in contrast to $\beta$-FeSe$_{1-x}$, monophasic superconducting $\d...
1006.0073v2
2010-07-23
Phonon-induced resistance oscillations of two-dimensional electron systems drifting with supersonic velocities
We present a theory of the phonon-assisted nonlinear dc transport of 2D electrons in high Landau levels. The nonlinear dissipative resistivity displays quantum magneto-oscillations governed by two parameters which are proportional to the Hall drift velocity $v_H$ of electrons in electric field and the speed of sound $s...
1007.4211v1
2010-07-26
Quantum phase transition of dynamical resistance in a mesoscopic capacitor
We study theoretically dynamic response of a mesoscopic capacitor, which consists of a quantum dot connected to an electron reservoir via a point contact and capacitively coupled to a gate voltage. A quantum Hall edge state with a filling factor nu is realized in a strong magnetic field applied perpendicular to the two...
1007.4404v1
2010-08-12
Single crystal growth and superconducting properties of LiFeAs
We report the successful growth of high quality single crystals of LiFeAs with lateral sizes up to 5 x 5 mm2 by the Sn-flux method. Electrical resistivity studies reveal that the superconducting onset temperature is 18.2 K with a transition width less than 1.1 K and the ratio of room temperature to residual resistivity...
1008.2050v1
2010-09-07
Mesoscopic transport in ultrathin films of La$_{0.67}$Ca$_{0.33}$MnO$_3$
We investigate the electrical transport in mesoscopic structures of La$_{0.67}$Ca$_{0.33}$MnO$_3$ in the regime of the metal-insulator transition by fabricating microbridges from strained and unstrained thin films. We measure current-voltage characteristics as function of temperature and in high magnetic fields and wit...
1009.1386v1
2010-09-28
Influence of disorder on conductance in bilayer graphene under perpendicular electric field
Electron transport in bilayer graphene placed under a perpendicular electric field is revealed experimentally. Steep increase of the resistance is observed under high electric field; however, the resistance does not diverge even at low temperatures. The observed temperature dependence of the conductance consists of two...
1009.5467v1
2010-11-18
Vortex density waves and negative absolute resistance in patterned superconductors
We study theoretically dynamical phases of vortices in superconducting films with arrays of obstacles. By performing a series of molecular dynamics simulations and analytical calculations, we demonstrate the existence of a phase of soliton-like vortex-density waves appearing in a wide range of parameters. These waves a...
1011.4172v2
2010-12-03
Magnetic and electrical properties and carrier doping effects on the Fe-based host compound Sr4Sc2Fe2As2O6
Additional charge carriers were introduced to the iron oxyarsenide Sr4Sc2Fe2As2O6 under a high-pressure condition, followed by measurements of electrical resistivity, Hall coefficient, and magnetic susceptibility. The host compound Sr4Sc2Fe2As2O6 shows metallic conductivity down to ~200 K and turns to show a semiconduc...
1012.0616v1
2010-12-06
An analytical model of fractional overshooting
We predict resistance anomalies to be observed at high mobility two dimensional electron systems (2DESs) in the fractional quantized Hall regime, where the narrow (L <10 ?m) Hall bar is defined by top gates. An analytic calculation scheme is used to describe the formation of integral and fractional incompressible strip...
1012.1294v1
2010-12-31
Beam test of signal cross-talk and transmission for LMPRC
A new prototype of large area Multi-gap Resistive Plate Chamber (MRPC) with long readout strips was built. This Long-strip Multi-gap Resistive Plate Chamber (LMRPC) is double stacked and has ten 250 $\mu$m-thick gas gaps. Signals are read out from two ends of strip with an active area of 50 cm$\times$2.5 cm in each. Th...
1101.0224v1
2011-02-10
Stimulated emission and absorption of photons in magnetic point contacts: toward metal-based spin-lasers
Point contacts between high anisotropy ferromagnetic SmCo5 and normal metal Cu are used to achieve a strong spin-population inversion in the contact core. Subjected to microwave irradiation in resonance with the Zeeman splitting in Cu, the inverted spin-population relaxes through stimulated spin-flip photon emission, d...
1102.2167v1
2011-02-14
Edge effect on resistance scaling rules in graphene nanostructures
We report an experimental investigation of the edge effect on the room-temperature transport in graphene nanoribbon and graphene sheet (both single-layer and bilayer). By measuring the resistance scaling behaviors at both low and high carrier densities, we show that the transport of single-layer nanoribbons lies in a s...
1102.2681v1
2011-02-20
In situ TEM investigation of oxygen migration as a key mechanism for resistive switching in Pr0.7Ca0.3MnO3
Low temperature growth Pr0.7Ca0.3MnO3 (PCMO) thin film showed high performance in electric field induced resistance switching (RS). To understand the micro-mechanism of RS in Metal/PCMO/Metal devices, structure evolution of PCMO under external electric field monitored inside transmission electron microscope (TEM) were ...
1102.4044v3
2011-05-19
Enhancement of the Superconducting Transition Temperature with Hydrostatic Pressure in Ca_{3}Ir_{4}Sn_{13} Single Crystals
We report high pressure magnetic susceptibility and electrical resistivity measurements on Ca_{3}Ir_{4}Sn_{13} single crystals up to 60 kbar. These measurements allow us to follow the evolution of the superconducting critical temperature T_c, the resistivity anomaly temperature T*, the superconducting coherence length ...
1105.3941v1
2011-05-24
Low Bias Negative Differential Resistance in Graphene Nanoribbon Superlattices
We theoretically investigate negative differential resistance (NDR) for ballistic transport in semiconducting armchair graphene nanoribbon (aGNR) superlattices (5 to 20 barriers) at low bias voltages V_SD < 500 mV. We combine the graphene Dirac Hamiltonian with the Landauer-B\"uttiker formalism to calculate the current...
1105.4850v2
2011-10-22
Pressure Induced Metallization of BaMn2As2
The temperature and pressure dependent electrical resistivity rho(T,P) studies have been performed on BaMn2As2 single crystal in the 4.2 to 300 K range upto of 8.2 GPa to investigate the evolution of its ground state properties. The rho(T) shows a negative co-efficient of resistivity under pressure upto 3.2 GPa. The oc...
1110.4969v2
2011-10-24
Two coupled Josephson junctions: dc voltage controlled by biharmonic current
We study transport properties of two Josephson junctions coupled by an external shunt resistance. One of the junction (say, the first) is driven by an unbiased ac current consisting of two harmonics. The device can rectify the ac current yielding a dc voltage across the first junction. For some values of coupling stren...
1110.5287v3
2011-10-31
Resistivity saturation in a weakly interacting 2D Fermi liquid at intermediate temperatures
We report a highly unusual temperature dependence in the magnetoresistance of a weakly interacting high mobility 2D electron gas (2DEG) under a parallel magnetic field and when the current is perpendicular to the field. While the linear temperature dependence below 10 K and the exponential temperature dependence above ...
1111.0011v2
2011-11-14
Anomalous resistivity and the electron-polaron effect in the two-band Hubbard model with one narrow band
We search for anomalous normal and superconductive behavior in the two-band Hubbard model with one narrow band. We analyze the influence of electron-polaron effect and Altshuler-Aronov effect on effective mass enhancement and scattering times of heavy and light components in the clean case. We find anomalous behavior o...
1111.3135v1
2011-12-07
Low carrier concentration crystals of the topological insulator Bi$_2$Te$_2$Se
We report the characterization of Bi$_2$Te$_2$Se crystals obtained by the modified Bridgman and Bridgman-Stockbarger crystal growth techniques. X-ray diffraction study confirms an ordered Se-Te distribution in the inner and outer chalcogen layers, respectively, with a small amount of mixing. The crystals displaying hig...
1112.1648v1
2011-12-22
Field induced quantum-Hall ferromagnetism in suspended bilayer graphene
We have measured the magneto-resistance of freely suspended high-mobility bilayer graphene. For magnetic fields $B>1$ T we observe the opening of a field induced gap at the charge neutrality point characterized by a diverging resistance. For higher fields the eight-fold degenerated lowest Landau level lifts completely....
1112.5368v2