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2016-07-26
Experimental Observation of Topological Superconductivity and Majorana Zero Modes on beta-Bi2Pd Thin Films
Using a cryogenic scanning tunneling microscopy, we report the observation of topologically nontrivial superconductivity on a single material of \beta-Bi2Pd films grown by molecular beam epitaxy. The superconducting gap associated with spinless odd-parity pairing opens on the surface and appears much larger than the bu...
1607.07551v4
2016-07-28
Imaging current-induced switching of antiferromagnetic domains in CuMnAs
The magnetic order in antiferromagnetic (AF) materials is hard to control with external magnetic fields. However, recent advances in detecting and manipulating AF order electrically have opened up new prospects for these materials in basic and applied spintronics research. Using x-ray magnetic linear dichroism microsco...
1607.08478v2
2016-08-11
Evolution of Insulator-Metal Phase Transitions in Epitaxial Tungsten Oxide Films during Electrolyte-Gating
An interface between an oxide and an electrolyte gives rise to various processes as exemplified by electrostatic charge accumulation/depletion and electrochemical reactions such as intercalation/decalation under electric field. Here we directly compare typical device operations of those in electric double layer transis...
1608.03357v1
2016-10-15
Dynamical Conductivity of Dirac Materials
For graphene (a Dirac material) it has been theoretically predicted and experimentally observed that DC resistivity is proportional to $ T^4$ when the temperature is much less than Bloch- Gr\"{u}neisen ($\Theta_{BG}$) temperature and T linear in opposite case ($T>>\Theta_{BG}$). Going beyond the DC case, we investigate...
1610.04697v1
2016-10-18
Magnetic properties of low-moment ferrimagnetic Heusler Cr2CoGa thin films grown by molecular beam epitaxy
Recently, theorists have predicted many materials with a low magnetic moment and large spin-polarization for spintronic applications. These compounds are predicted to form in the inverse Heusler structure, however, many of these compounds have been found to phase segregate. In this study, ordered Cr2CoGa thin films wer...
1610.05808v1
2016-10-21
On the impact of strain on the electronic properties of InAs/GaSb quantum well systems
Electron-hole hybridization in InAs/GaSb double quantum well structures leads to the formation of a mini band gap. We experimentally and theoretically studied the impact of strain on the transport properties of this material system. Thinned samples were mounted to piezo electric elements to exert strain along the [011]...
1610.06776v1
2016-11-09
Parallel and series conduction model in Topological Insulators
In the past few years there has been a surge in the material science engineering in order to synthesize bulk insulating and surface metallic Topological Insulating (TI) materials. This quest is not only theoretically important but also promising from the novel application perspective. The dependence of temperature on r...
1611.02856v1
2016-12-11
Superconductivity in Se-doped new materials EuSr2Bi2S4F4 and Eu2SrBi2S4F4
From our powder x ray diffraction pattern, electrical transport and magnetic studies we report the effect of isovalent Se substitution at S sites in the newly discovered systems EuSr2Bi2S4F4 and Eu2SrBi2S4F4. We have synthesized two new variants of 3244 type superconductor with Eu replaced by Sr which is reported elsew...
1612.03415v1
2017-02-16
Millimeter-scale layered MoSe2 grown on sapphire and evidence for negative magnetoresistance
Molecular beam epitaxy technique has been used to deposit a single layer and a bilayer of MoSe 2 on sapphire. Extensive characterizations including in-situ and ex-situ measurements show that the layered MoSe 2 grows in a scalable manner on the substrate and reveals characteristics of a stoichiometric 2H-phase. The laye...
1702.05121v1
2017-06-16
Gate-tunable large magnetoresistance in an all-semiconductor spin-transistor-like device
A large spin-dependent and electric field-tunable magnetoresistance of a two-dimensional electron system (2DES) is a key ingredient for the realization of many novel concepts for spin-based electronic devices. The low magnetoresistance observed during the last decades in devices with lateral semiconducting (SC) transpo...
1706.05239v1
2017-06-19
Electrical signature of individual magnetic skyrmions in multilayered systems
Magnetic skyrmions are topologically protected whirling spin textures that can be stabilized in magnetic materials in which a chiral interaction is present. Their limited size together with their robustness against the external perturbations promote them as the ultimate magnetic storage bit in a novel generation of mem...
1706.05809v1
2017-06-26
The Sobering Reality of Perovskite/Si Tandem Solar Cells under Realistic Operating Conditions
Perovskite/Si tandem solar cells have the potential to considerably out-perform conventional solar cells. Under standard test conditions, perovskite/Si tandem solar cells already outperform the Si single junction. Under realistic conditions, however, as we show, those tandem solar cells are hardly more efficient than t...
1706.08610v1
2017-09-11
Signature of growth-deposition technique on the properties of PECVD and thermal SiO2
In this article, we report the process induced variation in the characteristics of PECVD deposited and thermally grown silicon dioxide (SiO2) thin film. We find key differences in the porosity, arrangement of the nano-pores, surface roughness, refractive index and electrical resistivity of the SiO2 thin films obtained ...
1709.03257v1
2017-10-10
Evidence of a topological Hall effect in Eu$_{1-x}$Sm$_x$TiO$_3$
We report on the observation of a possible topological Hall effect in thin films of the itinerant ferromagnet Eu1-xSmxTiO3. EuTiO3 and Eu0.955Sm0.045TiO3 films were grown by molecular beam epitaxy. The EuTiO3 film is insulating. The Hall resistivity of the Eu0.955Sm0.045TiO3 films exhibits the anomalous Hall effect bel...
1710.03729v1
2017-10-12
Thermal conductivity reduction in rough silicon nanomembranes
Nanostructured silicon is a promising material for thermoelectric conversion, because the thermal conductivity in silicon nanostructures can be strongly reduced with respect to that of bulk materials. We present thermal conductivity measurements, performed with the 3$\omega$ technique, of suspended monocrystalline sili...
1710.04403v1
2017-10-17
XPS study of the chemical stability of DyBa2Cu3O6+δ superconductor
The chemical stability of the powder DyBa2Cu3O6+{\delta} has been studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermal analysis at ambient conditions. The powder was subjected to mechanical processing in a ball mill-activator to accelerate chemical degradation. The kinetic regularities...
1710.06271v1
2017-10-27
Percolative nature of the dc paraconductivity in the cuprate superconductors
We present an investigation of the planar direct-current (dc) paraconductivity of the model cuprate material HgBa$_2$CuO$_{4+\delta}$ in the underdoped part of the phase diagram. The simple quadratic temperature-dependence of the Fermi-liquid normal-state resistivity enables us to extract the paraconductivity above the...
1710.10220v1
2017-10-31
Suppression of vacancies boosts thermoelectric performance in type-I clathrates
Intermetallic type-I clathrates continue to attract attention as promising thermoelectric materials. Here we present structural and thermoelectric properties of single crystalline Ba8(Cu,Ga,Ge,v)46, where v denotes a vacancy. By single crystal X-ray diffraction on crystals without Ga we find clear evidence for the pres...
1710.11536v1
2018-01-02
Edge-Grafted Molecular Junctions between Graphene Nanoplatelets: Applied Chemistry to Enhance Heat Transfer in Nanomaterials
The edge-functionalization of graphene nanoplatelets (GnP) was carried out exploiting diazonium chemistry, aiming at the synthesis of edge decorated nanoparticles to be used as building blocks in the preparation of engineered nanostructured materials for enhanced heat transfer. Indeed, both phenol functionalized and di...
1801.00859v1
2018-01-03
Ion-exchange synthesis and superconductivity at 8.6 K of Na2Cr3As3 with quasi-one-dimensional crystal structure
A new Cr-based quasi-one-dimensional superconductor Na2Cr3As3 was synthesized by an ion-exchange method in sodium naphthalenide solution. The crystals are thread-like and the structure was analyzed by X-ray diffraction with a noncentrosymmetric hexagonal space group P-6m2 (No. 187), in which the (Cr3As3)2- linear chain...
1801.01010v1
2018-01-04
Crystal growth and magnetic anisotropy in the spin-chain ruthenate Na$_2$RuO$_4$
We report single crystal growth, electrical resistivity $\rho$, anisotropic magnetic susceptibiltiy $\chi$, and heat capacity $C_p$ measurements on the one-dimensional spin-chain ruthenate Na$_2$RuO$_4$. We observe variable range hopping (VRH) behaviour in $\rho(T)$. The magnetic susceptibility with magnetic field perp...
1801.01524v1
2018-01-17
The simultaneous discharge of liquid and grains from a silo
The flow rate of water through an orifice at the bottom of a container depends on the hydrostatic pressure whereas for a dry granular material is nearly constant. But what happens during the simultaneous discharge of grains and liquid from a silo? By measuring the flow rate as a function of time, we found that: (i) dif...
1801.05747v1
2018-02-16
Levitated electromechanics: all-electrical cooling of charged nano- and micro-particles
We show how charged levitated nano- and micro-particles can be cooled by interfacing them with an $RLC$ circuit. All-electrical levitation and cooling is applicable to a wide range of particle sizes and materials, and will enable state-of-the-art force sensing within an electrically networked system. Exploring the cool...
1802.05928v3
2018-02-21
Design of Chern Insulating Phases in Honeycomb Lattices
The search for robust examples of the magnetic version of topological insulators, referred to as quantum anomalous Hall insulators or simply Chern insulators, so far lacks success. Our groups have explored two distinct possibilities based on multiorbital 3d oxide honeycomb lattices. Each has a Chern insulating phase ne...
1802.07411v1
2018-02-21
Meta-screening and permanence of polar distortion in metallized ferroelectrics
Ferroelectric materials are characterized by a spontaneous polar distortion. The behavior of such distortions in the presence of free charge is the key to the physics of metallized ferroelectrics in particular, and of structurally-polar metals more generally. Using first-principles simulations, here we show that a pola...
1802.07464v1
2018-04-09
Canted antiferromagnetism in phase-pure CuMnSb
We report the low-temperature properties of phase-pure single crystals of the half-Heusler compound CuMnSb grown by means of optical float-zoning. The magnetization, specific heat, electrical resistivity, and Hall effect of our single crystals exhibit an antiferromagnetic transition at $T_{\mathrm{N}} = 55~\mathrm{K}$ ...
1804.03223v1
2018-04-24
Electrical and thermal transport in coplanar polycrystalline graphene-hBN heterostructures
We present a theoretical study of electronic and thermal transport in polycrystalline heterostructures combining graphene (G) and hexagonal boron nitride (hBN) grains of varying size and distribution. By increasing the hBN grain density from a few percents to $100\%$, the system evolves from a good conductor to an insu...
1804.09272v2
2018-05-08
Relativistic Gurzhi effect in channels of Dirac materials
Charge transport in channel-shaped 2D Dirac systems is studied employing the Boltzmann equation. The dependence of the resistivity on temperature and chemical potential is investigated. An accurate understanding of the influence of electron-electron interaction and material disorder allows us to identify a parameter re...
1805.02987v2
2018-05-28
Phonon Fingerprints of CsPb2Br5 Single Crystals
CsPb2Br5 is a stable, water-resistant, material derived from CsPbBr3 perovskite and featuring two-dimensional Pb-Br framework separated by Cs layers. Both compounds can coexist at nano- length scale, which often produces conflicting optical spectroscopy results. We present a complete set of polarized Raman spectra of n...
1805.11181v1
2018-06-01
Flat bands and the physics of strongly correlated Fermi systems
Some materials can have the dispersionless parts in their electronic spectra. These parts are usually called flat bands and generate the corps of unusual physical properties of such materials. These flat bands are induced by the condensation of fermionic quasiparticles, being very similar to the Bose condensation. The ...
1806.00438v1
2018-06-19
Influence of Interfaces on the Transport Properties of Graphite revealed by Nanometer Thickness Reduction
We investigated the influence of thickness reduction on the transport properties of graphite microflakes. Using oxygen plasma etching we decreased the thickness of highly oriented pyrolytic graphite (HOPG) microflakes from $\sim 100$~nm to $\sim 20$~nm systematically. Keeping current and voltage electrodes intact, the ...
1806.07417v3
2018-06-20
Concurrent transitions in wear rate and surface microstructure in nanocrystalline Ni-W
Nanocrystalline metals are promising materials for wear-resistant applications due to their superior strength and hardness, but prior work has shown that cyclic loading can lead to coarsening. In this study, scratch wear tests were carried out on nanocrystalline Ni-19 at.% W films with an as-deposited grain size of 3 n...
1806.07919v2
2018-06-27
Spin splitting induced in a superconductor by an antiferromagnetic insulator
Inspired by recent feats in exchange coupling antiferromagnets to an adjacent material, we demonstrate the possibility of employing them for inducing spin splitting in a superconductor, thereby avoiding the detrimental, parasitic effects of ferromagnets employed to this end. We derive the Gor'kov equation for the matri...
1806.10356v2
2019-08-30
Efficient Pourbaix diagrams of many-element compounds
Pourbaix diagrams have long been an essential tool for determining the phase stability of solids and their associated ionic species under electrochemical conditions. In recent years, Pourbaix diagrams have been used for applications ranging from corrosion-resistance alloy design to electrocatalysis, and the data from w...
1909.00035v1
2019-09-02
Nematic properties of FeSe$_{1-x}$Te$_{x}$ crystals with a low Te content
We report on the synthesis and physical properties of FeSe$_{1-x}$Te$_x$ single crystals with a low Te content (x = 0.17, 0.21, 0.25), where the replacement of Se with Te partially suppresses superconductivity. Resistivity and Hall effect measurements indicate weak anomalies at elevated temperatures ascribed to nematic...
1909.00711v1
2019-09-10
Ferroelectric enhancement of superconductivity in compressively strained SrTiO$_3$ films
SrTiO$_3$ is an incipient ferroelectric on the verge of a polar instability, which is avoided at low temperatures by quantum fluctuations. Within this unusual quantum paraelectric phase, superconductivity persists despite extremely dilute carrier densities. Ferroelectric fluctuations have been suspected to play a role ...
1909.04782v1
2014-08-07
Magneto-transport properties of oriented Mn2CoAl films sputtered on thermally oxidized Si substrates
Spin gapless semiconductors are interesting novel class of materials by embracing both magnetism and semiconducting. Its potential application in future spintronics requires realization in thin film form. In this letter, we report a successful growth of spin gapless Mn2CoAl films on thermally oxidized Si substrates by ...
1408.1547v1
2017-03-06
Pressure-Induced Insulator-to-Metal Transition Provides Evidence for Negative-$U$ Centers in Large-Gap Disordered Insulators
Attractive negative-$U$ interactions between electrons facilitated by strong electron-phonon interaction are common in highly polarizable and disordered materials such as amorphous chalcogenides, but there is no direct evidence for them in large-band-gap insulators. Here we report how such negative-$U$ centers are resp...
1703.02003v1
2017-03-20
Optimized spin-injection efficiency and spin MOSFET operation based on low-barrier ferromagnet/insulator/n-Si tunnel contact
We theoretically investigate the spin injection in different FM/I/n-Si tunnel contacts by using the lattice NEGF method. We find that the tunnel contacts with low barrier materials such as TiO$_2$ and Ta$_{2}$O$_{5}$, have much lower resistances than the conventional barrier materials, resulting in a wider and attainab...
1703.06835v3
2013-12-24
All-Metallic Electrically-Gated Tantalum Diselenide Switches and Logic Circuits
We report the fabrication and performance of all-metallic three-terminal devices with tantalum diselenide thin-film conducting channels. For this proof-of-concept demonstration, the layers of 2H-TaSe2 were exfoliated mechanically from single crystals grown by the chemical vapor transport method. Devices with nanometer-...
1312.6863v1
2014-10-27
Giant supercurrent states in a superconductor-InAs/GaSb-superconductor junction
Superconductivity in topological materials has attracted a great deal of interest in both electron physics and material sciences since the theoretical predictions that Majorana fermions can be realized in topological superconductors [1-4]. Topological superconductivity could be realized in a type II, band-inverted, InA...
1410.7342v3
2014-10-30
Kondo effect and non-Fermi liquid behavior in Dirac and Weyl semimetals
We study the Kondo effect in three-dimensional (3D) Dirac materials and Weyl semimetals. We find the scaling of the Kondo temperature with respect to the doping $n$ and the coupling $J$ between the moment of the magnetic impurity and the carriers of the semimetal. We find that when the temperature is much smaller than ...
1410.8532v2
2014-11-07
Temperature evolution of magnetic and transport behavior in 5\textit{d} Mott insulator Sr$_2$IrO$_4$: Significance of magneto-structural coupling
We have investigated the temperature evolution of magnetism and its interrelation with structural parameters in perovskite-based layered compound Sr$_2$IrO$_4$, which is believed to be a $J_{eff}$ = 1/2 Mott insulator. The structural distortion plays an important role in this material which induces a weak ferromagnetis...
1411.1946v1
2014-11-19
Electronic structure and transport properties of Cu-deficient kuramite Cu3-xSnS4
Electrical and thermal transport properties of Cu-deficient kuramite Cu3-xSnS4 (CTS) was examined as a possible earth-abundant thermoelectric material. Crystallographic structure of CTS was characterized by partial disorder between Cu and Sn. In contrast to semiconducting electrical transport of related compounds, such...
1411.5122v2
2015-05-20
III-V/Si Wafer Bonding Using Transparent, Conductive Oxide Interlayers
We present a method for low temperature plasma-activated direct wafer bonding of III-V materials to Si using a transparent, conductive indium zinc oxide interlayer. The transparent, conductive oxide (TCO) layer provides excellent optical transmission as well as electrical conduction, suggesting suitability for Si/III-V...
1505.05453v2
2016-06-10
Pressure sensing using vertically aligned carbon nanotubes on a flexible substrate
Sensing technologies have been under research and development for their varied applications from microelectronics to space exploration. With the end of Moores law in sight, there is growing demand for shrinking materials and improving sensitivity and range of sensing of sensors. Carbon nanotubes (CNTs) offer an excelle...
1606.03190v1
2016-06-18
Failure mechanisms of single-crystal silicon electrodes in lithium-ion batteries
Long-term durability is a major obstacle limiting the widespread use of lithium ion batteries (LIBs) in heavy-duty applications and others demanding extended lifetime. As one of the root causes of degradation and failure of battery performance, the electrode failure mechanisms are still unknown. Here, we reveal the fun...
1606.06283v1
2016-06-26
(CaO)(FeSe): A Layered Wide Gap Oxychalcogenide Semiconductor
A new iron-oxychalcogenide (CaO)(FeSe) was obtained which crystallizes in the orthorhombic space group Pnma (No. 62) with a = 5.9180(12) {\AA}, b = 3.8802(8) {\AA}, c = 13.193(3) {\AA}. The unique structure of (CaO)(FeSe) is built up of a quasi-two-dimensional network of corrugated infinite layers of corner-shared FeSe...
1606.08000v1
2017-01-17
Strange metal state near a heavy-fermion quantum critical point
Recent experiments on quantum criticality in the Ge-substituted heavy-electron material YbRh2Si2 under magnetic field have revealed a possible non-Fermi liquid (NFL) strange metal (SM) state over a finite range of fields at low temperatures, which still remains a puzzle. In the SM region, the zero-field antiferromagnet...
1701.04599v1
2017-01-17
Lifshitz transition mediated electronic transport anomaly in bulk ZrTe5
Zirconium pentatelluride ZrTe$_5$, a fascinating topological material platform, hosts exotic chiral fermions in its highly anisotropic three-dimensional Dirac band and holds great promise advancing the next-generation information technology. However, the origin underlying its anomalous resistivity peak has been under d...
1701.04737v2
2017-01-26
Spin mediated magneto-electro-thermal transport behavior in Ni80Fe20/MgO/p-Si thin films
In Si, spin-phonon interaction is the primary spin relaxation mechanism. At low temperatures, the absence of spin-phonon relaxation will lead to enhanced spin accumulation. Spin accumulation may change the electro-thermal transport within the material, and thus may serve as an investigative tool for characterizing spin...
1701.07854v2
2017-11-27
Extreme magnetoresistance induced by Zeeman effect-driven electron-hole compensation and topological protection in MoSi$_2$
The magnetoresistance is the magnetic field induced change of electrical resistivity of a material. Recent studies have revealed extremely large magnetoresistance in several non-magnetic semimetals, which has been explained on the basis of either electron-hole compensation or the Fermi surface topology, or the combinat...
1711.09646v1
2017-11-30
Experimental observation of node-line-like surface states in LaBi
In a Dirac nodal line semimetal, the bulk conduction and valence bands touch at extended lines in the Brillouin zone. To date, most of the theoretically predicted and experimentally discovered nodal lines derive from the bulk bands of two- and three-dimensional materials. Here, based on combined angle-resolved photoemi...
1711.11174v2
2017-12-19
Synthesis, Crystal Structure, and Physical Properties of New Layered Oxychalcogenide La2O2Bi3AgS6
We have synthesized a new layered oxychalcogenide La2O2Bi3AgS6. From synchrotron X-ray diffraction and Rietveld refinement, the crystal structure of La2O2Bi3AgS6 was refined using a model of the P4/nmm space group with a = 4.0644(1) {\AA} and c = 19.412(1) {\AA}, which is similar to the related compound LaOBiPbS3, whil...
1712.06726v1
2017-12-05
A Holistic Approach to Evaluate EMI Shielding Characteristics of Carbon Nanotube-based Polymer Composites
The work presents a comprehensive methodology to determine the Shielding Effectiveness (SE) of single-walled carbon nanotubes (SWCNTs)/polymer nanocomposites. Here, an algorithm based on Ant Colony Optimization (ACO) was employed to determine the electrical conductivity ({\sigma}) of these nanocomposites as a function ...
1712.08188v1
2018-10-13
Tuning the electronic structures and transport properties of zigzag blue phosphorene nanoribbons
In recent years, single element two-dimensional atom crystal materials have aroused extensive interest in many applications. Blue phosphorus, successfully synthesized on Au substrate by molecular beam epitaxy not long ago, shows unusual geometrical and electronic structures. We investigate the electronic structures and...
1810.05792v1
2018-10-18
Coating of Aluminum Alloys by Micro Arc Oxidation in Nitrate Salt
Plasma electrolytic oxidation (PEO) is a process for obtaining oxide coatings on valve metals. Mostly PEO is done in an aqueous solution electrolyte which limits the size of treated parts due to the system heating up. In presented work an alternative method of PEO processing applied in aluminum 1050 alloy in nitrate mo...
1810.08018v1
2018-11-26
Synthesis of Oxidation-Resistant Electrochemical-Active Copper Nanowires Using Phenylenediamine Isomers
Phenylenediamine (PDA) was chosen as a coordinating, reducing, and capping agent to effectively direct growth and protect against oxidation of Cu nanowires (Cu NWs) in an aqueous solution. PDA was found to reduce Cu (II) to Cu (I) at room temperature, and stabilize the resulting Cu (I) by forming a coordination complex...
1811.10510v1
2019-01-31
Unconventional Bloch-Grüneisen scattering in hybrid Bose-Fermi systems
We report on the novel mechanism of electron scattering in hybrid Bose-Fermi systems consisting of a two-dimensional electron gas in the vicinity of an exciton condensate: We show that a pair-of-bogolons--mediated scattering proves to be dominating over the conventional acoustic phonon channel and over the single-bogol...
1902.01214v1
2019-02-14
Charge transport in oxygen-deficient EuTiO$_3$: the emerging picture of dilute metallicity in quantum-paraelectric perovskite oxides
We report on a study of charge transport in EuTiO$_{3-\delta}$ single crystals with carrier density tuned across several orders of magnitude. Comparing this system with other quasi-cubic perovskites, in particular strontium titanate, we draw a comprehensive picture of metal-insulator transition and dilute metallicity i...
1902.05512v2
2019-02-27
Stokes flow analogous to viscous electron current in graphene
Electron transport in two-dimensional conducting materials such as graphene, with dominant electron-electron interaction, exhibits unusual vortex flow that leads to a nonlocal current-field relation (negative resistance), distinct from the classical Ohm's law. The transport behavior of these materials is best described...
1902.10383v1
2019-06-30
Dissipative-regime measurements as a tool for confirming and characterizing near-room-temperature superconductivity
The search for new superconducting materials approaching room temperature benefits from having a variety of testing methodologies to confirm and characterize the presence of superconductivity. Often the first signatures of new superconducting species occur incompletely and in very small volume fractions. These trace am...
1907.00425v1
2019-07-08
Theory of Spin Injection in Two-dimensional Metals with Proximity-Induced Spin-Orbit Coupling
Spin injection is a powerful experimental probe into a wealth of nonequilibrium spin-dependent phenomena displayed by materials with spin-orbit coupling (SOC). Here, we develop a theory of coupled spin-charge diffusive transport in two-dimensional spin-valve devices. The theory describes a realistic proximity-induced S...
1907.03727v1
2019-07-09
Low-Temperature Dielectric Anomalies at the Mott Insulator-Metal Transition
The correlation-driven Mott transition is commonly characterized by a drop in resistivity across the insulator-metal phase boundary; yet, the complex permittivity provides a deeper insight into the microscopic nature. We investigate the frequency- and temperature-dependent dielectric response of the Mott insulator $\ka...
1907.04437v2
2019-07-20
Generating Optimal Grasps Under A Stress-Minimizing Metric
We present stress-minimizing (SM) metric, a new metric of grasp qualities. Unlike previous metrics that ignore the material of target objects, we assume that target objects are made of homogeneous isotopic materials. SM metric measures the maximal resistible external wrenches without causing fracture in the target obje...
1907.08749v1
2019-07-23
Electronic transport in thin films of BaPbO$_3$: Unraveling two-dimensional quantum effects
Recently, perovskite related BaPbO$_3$ has attracted attention due to its hidden topological properties and, moreover, has been used as a thin layer in heterostructures to induce two-dimensional superconductivity. Here we investigate the normal state electronic transport properties of thin films of BaPbO$_3$. Temperatu...
1907.09839v2
2019-07-28
Magneto-ionic control of spin polarization in magnetic tunnel junctions
Magnetic tunnel junctions (MTJs) with Hf0.5Zr0.5O2 barriers are reported to show both tunneling magnetoresistance effect (TMR) and tunneling electroresistance effect (TER), displaying four resistance states by magnetic and electric field switching. Here we show that, under electric field cycling of large enough magnitu...
1907.12111v1
2020-02-11
On the Mechanical and Thermal Stability of Free-standing Monolayer Amorphous Carbon
Recently (C.-T. Toh et al., Nature 577, 199 (2020)), the first synthesis of free-standing monolayer amorphous carbon (MAC) was achieved. MAC is a pure carbon structure composed of five, six, seven and eight atom rings randomly distributed. MAC proved to be surprisingly stable and highly fracture resistant. Its electron...
2002.04682v1
2020-02-28
Evidence for metastable photo-induced superconductivity in K$_3$C$_{60}$
Far and mid infrared optical pulses have been shown to induce non-equilibrium unconventional orders in complex materials, including photo-induced ferroelectricity in quantum paraelectrics, magnetic polarization in antiferromagnets and transient superconducting correlations in the normal state of cuprates and organic co...
2002.12835v1
2020-03-20
Quantum Fluctuations in the Non-Fermi Liquid System CeCo$_{2}$Ga$_{8}$ Investigated Using $μ$SR
Reduced dimensionality offers a crucial information in deciding the type of the quantum ground state in heavy fermion materials. Here we have examined stoichiometric CeCo$_{2}$Ga$_{8}$ compound, which crystallizes in a quasi-one-dimensional crystal structure with Ga-Ce-Co chains along the $c$-axis. The low-temperature ...
2003.09104v1
2020-03-28
Superconductivity in the nonsymmorphic line-nodal compound CaSb$_2$
We found superconductivity in CaSb$_2$ with the transition temperature of 1.7 K by means of electrical-resistivity, magnetic-susceptibility, and specific-heat measurements. This material crystallizes in a nonsymmorphic structure and is predicted to have multiple Dirac nodal lines in the bulk electronic band structure p...
2003.12800v1
2020-02-25
Advanced protection against environmental degradation of silver mirror stacks for space application
Protection of silver mirror stacks from environmental degradation before launching is crucial for space applications. Hereby, we report a comparative study of the advanced protection of silver mirror stacks for space telescopes provided by SiO2 and Al2O3 coatings in conditions of accelerated aging by sulfidation. The m...
2004.06590v1
2020-04-20
Lindemann unjamming of emulsions
We study the bulk and shear elastic properties of barely-compressed, "athermal" emulsions and find that the rigidity of the jammed solid fails at remarkably large critical osmotic pressures. The minuscule yield strain and similarly small Brownian particle displacement of solid emulsions close to this transition suggest...
2004.09594v2
2020-09-07
Quantum Sensing of Insulator-to-Metal Transitions in a Mott Insulator
Nitrogen vacancy (NV) centers, optically-active atomic defects in diamond, have attracted tremendous interest for quantum sensing, network, and computing applications due to their excellent quantum coherence and remarkable versatility in a real, ambient environment. Taking advantage of these strengths, we report on NV-...
2009.02886v1
2020-09-09
Population Dynamics Model and Analysis for Bacteria Transformation and Conjugation
We present a two-species population model in a well-mixed environment where the dynamics involves, in addition to birth and death, changes due to environmental factors and inter-species interactions. The novel dynamical components are motivated by two common mechanisms for developing antibiotic resistance in bacteria: ...
2009.04276v1
2020-09-28
Two-dimensional Janus van der Waals heterojunctions: a review of recent research progresses
Two-dimensional Janus van der Waals (vdW) heterojunctions, referring to the junction containing at least one Janus material, are found to exhibit tuneable electronic structures, wide light adsorption spectra, controllable contact resistance, and sufficient redox potential due to the intrinsic polarization and unique in...
2009.12985v1
2022-02-11
Unusual electrical and magnetic properties in layered EuZn2As2
Eu-based compounds often exhibit unusual magnetism, which is critical for nontrivial topological properties seen in materials such as EuCd2As2. We investigate the structure and physical properties of EuZn2As2 through measurements of the electrical resistivity, Hall effect, magnetization, and neutron diffraction. Our da...
2202.05884v1
2022-02-16
Emergence of Intergranular Tunneling Dominated Negative Magnetoresistance in Helimagnetic Manganese Phosphide Nanorod Thin Films
Helical magnets are emerging as a novel class of materials for spintronics and sensor applications; however, research on their charge and spin transport properties in a thin film form is less explored. Herein, we report the temperature and magnetic field dependent charge transport properties of a highly crystalline MnP...
2202.07915v1
2014-01-30
Infrared luminescence in Bi-doped Ge-S and As-Ge-S chalcogenide glasses and fibers
Experimental and theoretical studies of spectral properties of chalcogenide Ge-S and As-Ge-S glasses and fibers are performed. A broad infrared (IR) luminescence band which covers the 1.2-2.3~$\mu$m range with a lifetime about 6~$\mu$s is discovered. Similar luminescence is also present in optical fibers drawn from the...
1401.7815v1
2016-03-02
Energy filtering enhancement of thermoelectric performance of nanocrystalline Cr-Si composites
We report on thermoelectric properties of nanocrystalline Cr$_{\rm 1-x}$Si$_{\rm x}$ composite films. As-deposited amorphous films were transformed into a nanocrystalline state with average grain size of 10--20~nm by annealing during in-situ thermopower and electrical resistivity measurements. The partially crystallize...
1603.00626v4
2016-03-07
Tuning of thermoelectric properties with changing Se content in Sb2Te3
Polycrystalline Sb 2 Te 3-x Se x (0.0 < x < 1.0) samples were synthesized by the solid state reaction method. The structural analysis showed that up to the maximal concentration of Se, the samples possess the Rhombohedral crystal symmetry (space group R 3 m ). Increase of Se content increases the resistivity of the sam...
1603.01998v1
2016-03-28
Mechanism for the Large Conductance Modulation in Electrolyte-gated Thin Gold Films
Electrolyte gating using ionic liquid electrolytes has recently generated considerable interest as a method to achieve large carrier density modulations in a variety of materials. In noble metal thin films, electrolyte gating results in large changes in sheet resistance. The widely accepted mechanism for these changes ...
1603.08286v1
2017-04-05
Superconductivity at 33 - 37 K in $ALn_2$Fe$_4$As$_4$O$_2$ ($A$ = K and Cs; $Ln$ = Lanthanides)
We have synthesized 10 new iron oxyarsenides, K$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Gd, Tb, Dy, and Ho) and Cs$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Nd, Sm, Gd, Tb, Dy, and Ho), with the aid of lattice-match [between $A$Fe$_2$As$_2$ ($A$ = K and Cs) and $Ln$FeAsO] approach. The resultant compounds possess hole-doped conducting dou...
1704.01488v1
2017-04-09
Properties of In-Plane Graphene/MoS2 Heterojunctions
The graphene/MoS2 heterojunction formed by joining the two components laterally in a single plane promises to exhibit a low-resistance contact according to the Schottky-Mott rule. Here we provide an atomic-scale description of the structural, electronic, and magnetic properties of this type of junction. We first identi...
1704.02669v1
2017-04-11
Neutron powder diffraction study on the iron-based nitride superconductor ThFeAsN
We report neutron diffraction and transport results on the newly discovered superconducting nitride ThFeAsN with $T_c=$ 30 K. No magnetic transition, but a weak structural distortion around 160 K, is observed cooling from 300 K to 6 K. Analysis on the resistivity, Hall transport and crystal structure suggests this mate...
1704.03119v1
2017-04-29
Infrared-transmittance tunable metal-insulator conversion device with thin-film-transistor-type structure on a glass substrate
Infrared (IR) transmittance tunable metal-insulator conversion was demonstrated on glass substrate by using thermochromic vanadium dioxide (VO2) as the active layer in three-terminal thin-film-transistor-type device with water-infiltrated glass as the gate insulator. Alternative positive/negative gate-voltage applicati...
1705.00130v1
2017-05-02
Nodeless superconductivity and the peak effect in the quasi-skutterudites $\mathrm{Lu}_3\mathrm{Os}_4\mathrm{Ge}_{13}$ and $\mathrm{Y}_3\mathrm{Ru}_4\mathrm{Ge}_{13}$
We report an investigation of the superconducting states of $\mathrm{Lu}_3\mathrm{Os}_4\mathrm{Ge}_{13}$ and $\mathrm{Y}_3\mathrm{Ru}_4\mathrm{Ge}_{13}$ single crystals by measurements of the electrical resistivity, ac susceptibility and London penetration depth. The analysis of the penetration depth and the derived su...
1705.00818v1
2017-05-15
Novel metal-insulator-transition at the SrTiO3/SmTiO3 interface
We report on a metal-insulator transition (MIT) that is observed in an electron system at the SmTiO3/SrTiO3 interface. This MIT is characterized by an abrupt transition at a critical temperature, below which the resistance changes by more than an order of magnitude. The temperature of the transition systematically depe...
1705.05447v1
2017-07-11
Strain-dependent solid surface stress and the stiffness of soft contacts
Surface stresses have recently emerged as a key player in the mechanics of highly compliant solids. The classic theories of contact mechanics describe adhesion with a compliant substrate as a competition between surface energies driving deformation to establish contact and bulk elasticity resisting this. However, it ha...
1707.03089v1
2017-08-02
Review on Modeling of Mechanical and Thermal Properties of Nano- and Micro-Composites
This article deals with the prediction of thermomechanical properties of fiber reinforced composites using several micromechanics models. These include strength of material approach, Halpin-Tsai equations, multi-phase mechanics of materials approaches, multi-phase Mori-Tanaka models, composite cylindrical assemblage mo...
1708.00764v1
2017-08-10
Observation of two-dimensional Fermi surface and Dirac dispersion in YbMnSb$_2$
We present the crystal structure, electronic structure, and transport properties of the material YbMnSb$_2$, a candidate system for the investigation of Dirac physics in the presence of magnetic order. Our measurements reveal that this system is a low-carrier-density semimetal with a 2D Fermi surface arising from a Dir...
1708.03308v1
2018-08-06
Short Note on Superconductivity at Ambient Temperature and Pressure in Silver Embedded Gold Nano-particles: A Goldsmith job ahead
Very recent observation of superconductivity in both transport (resistance versus temperature) and magnetization (Zero field cooled) at around 235 K has obviously raised many eyebrows. The experimental fraternity in particular is more thrilled. Although the results presented in the paper are clean and both transport an...
1808.01797v2
2018-08-12
A Facile Approach to Prepare Self-Assembled, Nacre-Inspired Clay/Polymer Nano-Composites
Nature provides many paradigms for the design and fabrication of artificial composite materials. Inspired by the relationship between the well-ordered architecture and biopolymers found in natural nacre, we present a facile strategy to construct large-scale organic/inorganic nacre-mimetics with hierarchical structure v...
1808.03972v1
2019-03-16
Fundamental limits to radiative heat transfer: the limited role of nanostructuring in the near field
In a complementary article, we exploited algebraic properties of Maxwell's equations and fundamental principles such as electromagnetic reciprocity and passivity, to derive fundamental limits to radiative heat transfer applicable in near- through far-field regimes. The limits depend on the choice of material susceptibi...
1903.07968v3
2019-04-17
Low temperature saturation of phase coherence length in topological insulators
Implementing topological insulators as elementary units in quantum technologies requires a comprehensive understanding of the dephasing mechanisms governing the surface carriers in these materials, which impose a practical limit to the applicability of these materials in such technologies requiring phase coherent trans...
1904.08517v1
2019-08-28
A Cantilever Torque Magnetometry Method for the Measurement of Hall Conductivity of Highly Resistive Samples
We present the first measurements of Hall conductivity utilizing a new torque magnetometry method designed for insulators. A Corbino disk exhibits a magnetic dipole moment proportional to Hall conductivity when voltage is applied across a test material. This magnetic dipole moment can be measured through torque magneto...
1908.10857v3
2011-04-18
Manipulation of heat current by the interface between graphene and white graphene
We investigate the heat current flowing across the interface between graphene and hexagonal boron nitride (so-called white graphene) using both molecular dynamics simulation and nonequilibrium Green's function approaches. These two distinct methods discover the same phenomena that the heat current is reduced linearly w...
1104.3371v2
2012-06-17
The efficiency and power of the martensite rotor heat engine. I
The physical aspects - mechanics and thermodynamics - of operation of martensite rotor heat engine (MRHE) on the basis of martensite-austenite structural phase transition with the transition temperature in the region of low-potential water temperatures have been studied. The engine converts the thermal energy of low-po...
1206.3733v1
2012-06-29
Synthesis of a new alkali metal-organic solvent intercalated iron selenide superconductor with Tc{\approx}45K
We report on a new iron selenide superconductor with a TC onset of 45K and the nominal composition Lix(C5H5N)yFe2-zSe2, synthesized via intercalation of dissolved alkaline metal in anhydrous pyridine at room temperature. This superconductor exhibits a broad transition, reaching zero resistance at 10K. Magnetization mea...
1206.7022v1
2015-06-04
Thermal conductivity of bulk and nanoscaled Si/Ge alloys from the Kinetic Collective Model
Several hitherto unexplained features of thermal conductivity in group IV materials, such as the change in the slope as a function of sample size for pure vs. alloyed samples and the fast decay in thermal conductivity for low impurity concentration, are described in terms of a transition from a collective to kinetic re...
1506.01522v2