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2018-09-09
Efficient thermionic operation and phonon isolation by a semiconductor-superconductor junction
Control of heat flux at small length scales is crucial for numerous solid-state devices and systems. In addition to the thermal management of information and communication devices the mastering of heat transfer channels down to the nanoscale also enable, e.g., new memory concepts, high sensitivity detectors and sensors...
1809.02994v1
2018-11-02
Conformal printing of graphene for single and multi-layered devices on to arbitrarily shaped 3D surfaces
Printing has drawn a lot of attention as a means of low per-unit cost and high throughput patterning of graphene inks for scaled-up thin-form factor device manufacturing. However, traditional printing processes require a flat surface and are incapable of achieving patterning on to 3D objects. Here, we present a conform...
1811.01073v2
2018-11-12
Homogeneous Large-area Quasi-freestanding Monolayer and Bilayer Graphene on SiC
In this study, we first show that the argon flow during epitaxial graphene growth is an important parameter to control the quality of the buffer and the graphene layer. Atomic force microscopy (AFM) and low-energy electron diffraction (LEED) measurements reveal that the decomposition of the SiC substrate strongly depen...
1811.04998v1
2018-11-14
Giant anisotropy in superconducting single crystals of CsCa$_2$Fe$_4$As$_4$F$_2$
CsCa$_2$Fe$_4$As$_4$F$_2$ is a newly discovered iron-based superconductor with $T_\mathrm{c}\sim$ 30 K containing double Fe$_2$As$_2$ layers that are separated by insulating Ca$_2$F$_2$ spacer layers. Here we report the transport and magnetization measurements on CsCa$_2$Fe$_4$As$_4$F$_2$ single crystals grown for the ...
1811.05706v1
2019-02-01
Light Enhanced Blue Energy Generation using MoS$_2$ Nanopores
Blue energy relies on the chemical potential difference generated between solutions of high and low ionic strength and would provide a sun-and-wind independent energy source at estuaries around the world. Converting this osmotic energy through reverse-electrodialysis relies on ion-selective membranes. A novel generatio...
1902.00410v1
2019-02-25
Synaptic Learning and Memory Functions Achieved in Self-rectifying BFO Memristor under Extreme Environmental Temperature
Memristors have been intensively studied in recent years as promising building blocks for next-generation non-volatile memory, artificial neural networks and brain-inspired computing systems. Even though the environment adaptability of memristor has been required in many application fields, it has been rarely reported ...
1902.09081v1
2019-07-03
Probing defect states in few-layer MoS$_{2}$ by conductance fluctuation spectroscopy
Despite the concerted effort of several research groups, a detailed experimental account of defect dynamics in high-quality single- and few-layer transition metal dichalcogenides remain elusive. In this paper we report an experimental study of the temperature dependence of conductance and conductance-fluctuations on se...
1907.01830v1
2020-04-11
High-field depinned phase and planar Hall effect in skyrmion-host Gd$_2$PdSi$_3$
For the skyrmion-hosting intermetallic Gd$_2$PdSi$_3$ with centrosymmetric hexagonal lattice and triangular net of rare earth sites, we report a thorough investigation of the magnetic phase diagram. Our work reveals a new magnetic phase with isotropic value of the critical field for all orientations, where the magnetic...
2004.05385v1
2020-09-11
Electronic nematic states tuned by isoelectronic substitution in bulk FeSe1-xSx
Isoelectronic substitution is an ideal tuning parameter to alter electronic states and correlations in iron-based superconductors. As this substitution takes place outside the conducting Fe planes, the electronic behaviour is less affected by the impurity scattering experimentally and relevant key electronic parameters...
2009.05523v1
2020-09-23
Superconducting fluctuations in overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$
Fluctuating superconductivity - vestigial Cooper pairing in the resistive state of a material - is usually associated with low dimensionality, strong disorder or low carrier density. Here, we report single particle spectroscopic, thermodynamic and magnetic evidence for persistent superconducting fluctuations in heavily...
2009.10932v2
2020-09-29
Structural Phase Dependent Giant Interfacial Spin Transparency in W/CoFeB Thin Film Heterostructure
Pure spin current has transfigured the energy-efficient spintronic devices and it has the salient characteristic of transport of the spin angular momentum. Spin pumping is a potent method to generate pure spin current and for its increased efficiency high effective spin-mixing conductance (Geff) and interfacial spin tr...
2009.14143v1
2017-04-20
Accretion powered AGN feedback in the cores of galaxy clusters
Detection of the copious amount of X-ray emission from the dilute hot plasma in galaxy clusters suggests that a substantial fraction of the central intracluster medium (ICM) is cooling radiatively on a time scale much faster than the Hubble time. Theoretical models predict the cooling rate as high as about few hundred ...
1704.06047v1
2017-04-23
Steep-slope Hysteresis-free Negative Capacitance MoS2 Transistors
The so-called Boltzmann Tyranny defines the fundamental thermionic limit of the subthreshold slope (SS) of a metal-oxide-semiconductor field-effect transistor (MOSFET) at 60 mV/dec at room temperature and, therefore, precludes the lowering of the supply voltage and the overall power consumption. Adding a ferroelectric ...
1704.06865v2
2017-08-04
The cuprate phase diagram and the influence of nanoscale inhomogeneities
The phase diagram associated with the high Tc superconductors is complicated by an array of different ground states. The parent material represents an antiferromagnetic insulator but with doping superconductivity becomes possible with transition temperatures previously thought unattainable. The underdoped region of the...
1708.01558v2
2019-03-12
Precision Analysis of Evolved Stars
Evolved stars dominate galactic spectra, enrich the galactic medium, expand to change their planetary systems, eject winds of a complex nature, produce spectacular nebulae and illuminate them, and transfer material between binary companions. While doing this, they fill the HR diagram with diagnostic loops that write th...
1903.05109v1
2019-04-14
Superconducting Praseodymium Superhydrides
Superhydrides have complex hydrogenic sublattices and are important prototypes for studying metallic hydrogen and high-temperature superconductors. Encouraged by the results on LaH10, in consideration of the differences between La and Pr, Pr-H system is especially worth studying because of the magnetism and valence-ban...
1904.06643v2
2019-08-06
Hump-like structure in Hall signal from SrRuO$_3$ ultra-thin films without inhomogeneous anomalous Hall effect
A controversy arose over the interpretation of the recently observed hump features in Hall resistivity $\rho_{xy}$ from ultra-thin SrRuO$_3$ (SRO) film; it was initially interpreted to be due to topological Hall effect but was later proposed to be from existence of regions with different anomalous Hall effect (AHE). In...
1908.02083v1
2019-08-22
High-Pressure Synthesis of Magnetic Neodymium Polyhydrides
The current search for room-temperature superconductivity is inspired by the unique properties of the electron-phonon interaction in metal superhydrides. Encouraged by the recently found highest-$T_C$ superconductor fcc-$LaH_{10}$, here we discover several superhydrides of another lanthanide - neodymium. We identify th...
1908.08304v3
2019-12-27
Localized spin waves at low temperatures in a Cobalt Carbide nanocomposite
We study magnetic, transport and thermal properties of Cobalt carbide nanocomposite with a mixture of Co2C and Co3C phases in 1:1 ratio, with an average particle diameter of 40$\pm 15$ nm. We show that the behavior of the nanocomposite is completely different from that of either Co3C or Co2C. We observed that with decr...
1912.12085v1
2012-06-06
Irreversibility and time relaxation in electrostatic doping of oxide interfaces
Two-dimensional electron gas (2DEG) confined in quantum wells at insulating oxide interfaces have attracted much attention as their electronic properties display a rich physics with various electronics orders such as superconductivity and magnetism. A particularly exciting features of these hetero-structures lies in th...
1206.1198v1
2018-07-04
Doping effects of Cr on the physical properties of BaFe$_{1.9-x}$Ni$_{0.1}$Cr$_{x}$As$_{2}$
We present a systematic study on the heavily Cr doped iron pnictides BaFe$_{1.9-x}$Ni$_{0.1}$Cr$_{x}$As$_{2}$ by using elastic neutron scattering, high-resolution synchrotron X-ray diffraction (XRD), resistivity and Hall transport measurements. When the Cr concentration increases from $x=$ 0 to 0.8, neutron diffraction...
1807.01612v1
2018-07-26
Excitation and coherent control of spin qudit modes with sub-MHz spectral resolution
Quantum bit or qubit is a two-level system, which builds the foundation for quantum computation, simulation, communication and sensing. Quantum states of higher dimension, i.e., qutrits (D = 3) and especially qudits (D = 4 or higher), offer significant advantages. Particularly, they can provide noise-resistant quantum ...
1807.10383v1
2018-12-16
Anti-fatigue-fracture hydrogels
The emerging applications of hydrogels in devices and machines require these soft materials to maintain robustness under cyclic mechanical loads. Whereas hydrogels have been made tough to resist fracture under a single cycle of mechanical load, these toughened gels still suffer from fatigue fracture under multiple cycl...
1812.06403v1
2019-01-15
Use of Cernox thermometers in AC specific heat measurements under pressure
We report on the resistance behavior of bare-chip Cernox thermometers under pressures up to 2 GPa, generated in a piston-cylinder pressure cell. Our results clearly show that Cernox thermometers, frequently used in low-temperature experiments due to their high sensitivity, remain highly sensitive even under applied pre...
1901.05089v2
2019-10-07
High electrical conductivity of single metal-organic chains
Molecular wires are essential components for future nanoscale electronics. However, the preparation of individual long conductive molecules is still a challenge. MMX metal-organic polymers are quasi-one-dimensional sequences of single halide atoms (X) bridging subunits with two metal ions (MM) connected by organic liga...
1910.02834v1
2020-10-01
Universal limiting transition temperature for the high $T_\mathrm{c}$ superconductors
Since their discovery three decades ago it has emerged that the physics of high-$T_\mathrm{c}$ cuprate superconductors is characterised by multiple temperature scales, and a phenomenology that deviates significantly from the conventional paradigm of superconductivity. Below the "pseudogap" temperature, $T^*$, a range o...
2010.00572v1
2020-11-17
Shallow Valence Band of Rutile GeO$_2$ and P-type Doping
GeO$_2$ has an $\alpha$-quartz-type crystal structure with a very wide fundamental band gap of 6.6 eV and is a good insulator. Here we find that the stable rutile-GeO$_2$ polymorph with a 4.6 eV band gap has a surprisingly low $\sim$6.8 eV ionization potential, as predicted from the band alignment using first-principle...
2011.08928v1
2020-11-25
Evidence for freezing of charge degrees of freedom across a critical point in CeCoIn$_5$
The presence of a quantum critical point separating two distinct zero-temperature phases is thought to underlie the `strange' metal state of many high-temperature superconductors. The nature of this quantum critical point, as well as a description of the resulting strange metal, are central open problems in condensed m...
2011.12951v1
2020-12-03
Effect of ageing on the properties of the W-containing IRIS-TiAl alloy
The effects of ageing at 800 $^\circ$C on the properties of the IRIS alloy (Ti$_{49.9}$Al$_{48}$W$_2$B$_{0.1}$) are studied. The initial microstructure of this alloy densified by Spark Plasma Sintering (SPS) is mainly composed of lamellar colonies which are surrounded by $\gamma$ grains. The evolutions of the alloy str...
2012.01760v1
2020-12-03
First order transition in trigonal structure ${\textbf{Ca}}{\textbf{Mn}}_{2}{\textbf{P}}_{2}$
We report structural and physical properties of the single crystalline ${\mathrm{Ca}}{\mathrm{Mn}}_{2}{\mathrm{P}}_{2}$. The X-ray diffraction(XRD) results show that ${\mathrm{Ca}}{\mathrm{Mn}}_{2}{\mathrm{P}}_{2}$ adopts the trigonal ${\mathrm{Ca}}{\mathrm{Al}}_{2}{\mathrm{Si}}_{2}$-type structure. Temperature depende...
2012.01863v1
2021-02-10
Electropolishing of single crystal and polycrystalline aluminum to achieve high optical and mechanical surfaces
Electropolishing has found wide application as the final surface treatment of metal products in mechanical engineering and instrumentation, medicine and reflective concentrators for PV cells. It was found that electropolishing (EP) not only reduces the surface roughness and changes its appearance, but improves many ope...
2102.05752v1
2021-04-21
Electrically driven programmable phase-change meta-switch reaching 80% efficiency
Despite recent advances in active metaoptics, wide dynamic range combined with high-speed reconfigurable solutions is still elusive. Phase-change materials (PCMs) offer a compelling platform for metasurface optical elements, owing to the large index contrast and fast yet stable phase transition properties. Here, we exp...
2104.10381v2
2021-07-01
Solid Source Metal-Organic Molecular Beam Epitaxy of Epitaxial RuO2
A seemingly simple oxide with a rutile structure, RuO2 has been shown to possess several intriguing properties ranging from strain-stabilized superconductivity to a strong catalytic activity. Much interest has arisen surrounding the controlled synthesis of RuO2 films but, unfortunately, utilizing atomically-controlled ...
2107.00193v1
2021-08-02
PID-like active control strategy for electroacoustic resonators to design tunable single-degree-of-freedom sound absorbers
Sound absorption at low frequencies still remains a challenge in both scientific research and engineering practice. Natural porous materials are ineffective in this frequency range, as well as acoustic resonators which present too narrow bandwidth of absorption, thus requiring alternative solutions based on active abso...
2108.00765v1
2021-10-29
Supercurrent diode effect and magnetochiral anisotropy in few-layer NbSe$_2$
Nonreciprocal transport refers to charge transfer processes that are sensitive to the bias polarity. Until recently, nonreciprocal transport was studied only in dissipative systems, where the nonreciprocal quantity is the resistance. Recent experiments have, however, demonstrated nonreciprocal supercurrent leading to t...
2110.15752v2
2021-11-28
CoFeVSb: A Promising Candidate for Spin Valve and Thermoelectric Applications
We report a combined theoretical and experimental study of a novel quaternary Heusler system CoFeVSb from the view point of room temperature spintronics and thermoelectric applications. It crystallizes in cubic structure with small DO$_3$-type disorder. The presence of disorder is confirmed by room temperature synchrot...
2111.14081v1
2021-12-16
Constrained multi-objective optimization of process design parameters in settings with scarce data: an application to adhesive bonding
Adhesive joints are increasingly used in industry for a wide variety of applications because of their favorable characteristics such as high strength-to-weight ratio, design flexibility, limited stress concentrations, planar force transfer, good damage tolerance, and fatigue resistance. Finding the optimal process para...
2112.08760v3
2022-01-08
Are Heavy Fermion Strange Metals Planckian?
Strange metal behavior refers to a linear temperature dependence of the electrical resistivity at temperatures below the Mott-Ioffe-Regel limit. It is seen in numerous strongly correlated electron systems, from the heavy fermion compounds, via transition metal oxides and iron pnictides, to magic angle twisted bi-layer ...
2201.02820v1
2022-03-04
Character of the "normal state" of the nickelate superconductors
The occurrence of superconductivity in proximity to various strongly correlated phases of matter has drawn extensive focus on their normal state properties, to develop an understanding of the state from which superconductivity emerges. The recent finding of superconductivity in layered nickelates raises similar interes...
2203.02580v1
2022-03-22
Prediction of resistance induced by surface complexity in lubricating layers: Application to super-hydrophobic surfaces
Super Hydrophobic (SH) coatings are widely used to mitigate drag in various applications. Numerous studies have demonstrated that the beneficial wall-slip effect produced by these materials disappears in laminar flow regimes. The main mechanisms considered to be behind the decrease in performance are Marangoni-induced ...
2203.12039v1
2022-04-06
Thermal activation of low-density Ga implanted in Ge
The nuclear spins of low-density implanted Ga atoms in Ge are interesting candidates for solid state-based qubits. To date, activation studies of implanted Ga in Ge have focused on high densities. Here we extend activation studies into the low-density regime. We use spreading resistance profiling and secondary ion mass...
2204.02878v1
2022-05-05
Intrinsic spin Hall torque in a moire Chern magnet
In spin torque magnetic memories, electrically actuated spin currents are used to switch a magnetic bit. Typically, these require a multilayer geometry including both a free ferromagnetic layer and a second layer providing spin injection. For example, spin may be injected by a nonmagnetic layer exhibiting a large spin ...
2205.02823v1
2022-06-02
A multi-fidelity approach coupling parameter space reduction and non-intrusive POD with application to structural optimization of passenger ship hulls
Nowadays, the shipbuilding industry is facing a radical change towards solutions with a smaller environmental impact. This can be achieved with low emissions engines, optimized shape designs with lower wave resistance and noise generation, and by reducing the metal raw materials used during the manufacturing. This work...
2206.01243v3
2022-06-08
Dielectric properties and impedance spectroscopy of NASICON type Na$_3$Zr$_2$Si$_2$PO$_{12}$
We report the temperature dependent dielectric properties and impedance spectroscopy investigation of Na$_3$Zr$_2$Si$_2$PO$_{12}$ in the frequency range of 20 Hz--2 MHz. The Rietveld refinement of x-ray diffraction pattern confirms the monoclinic phase with C2/c space group. The {\it d.c.} resistivity behavior shows it...
2206.03668v1
2022-11-18
Synthesis of infinite-layer nickelates and influence of the capping-layer on magnetotransport
The recent discovery of a zero-resistance state in nickel-based compounds has generated a re-excitement about the long-standing problem in condensed matter of high-critical-temperature superconductivity, in light of the analogies between infinite-layer nickelates and cuprates. However, despite some formal valence and c...
2211.10251v1
2022-12-12
Unconventional localization of electrons inside of a nematic electronic phase
The magnetotransport behaviour inside the nematic phase of bulk FeSe reveals unusual multiband effects that cannot be reconciled with a simple two-band approximation proposed by surface-sensitive spectroscopic probes. In order to understand the role played by the multiband electronic structure and the degree of two-dim...
2212.06196v1
2023-01-19
Ab initio comparison of spin-transport properties in MgO-spaced ferrimagnetic tunnel junctions based on Mn$_3$Ga and Mn$_3$Al
We report on first-principles spin-polarised quantum transport calculations (from NEGF+DFT) in MgO-spaced magnetic tunnel junctions (MTJs) based on two different Mn-based Heusler ferrimagnetic metals, namely Mn$_3$Al and Mn$_3$Ga in their tetragonal DO$_{22}$ phase. The former is a fully compensated half-metallic ferri...
2301.08300v1
2023-05-09
Influence of Shape on Heteroaggregation of Model Microplastics: A Simulation Study
Nano- and microplastics are a growing threat for the environment, especially in aqueous habitats. For assessing the influence on the ecosystem and possible solution strategies, it is necessary to investigate the fate of microplastics (MP) in the environment. MPs are typically surrounded by natural organic matter, which...
2305.05453v1
2023-06-08
Epitaxial thin films of binary Eu-compounds close to a valence transition
Intermetallic binary compounds of europium reveal a variety of interesting phenomena due to the interconnection between two different magnetic and 4f electronic (valence) states, which are particularly close in energy. The valence states or magnetic properties are thus particularly sensitive to strain-tuning in these m...
2306.05355v2
2023-06-26
Phase purity and surface morphology of high-Jc superconducting Bi2Sr2Ca1Cu2O8+δ thin films
Bi2Sr2Ca1Cu2O8+d (Bi-2212) thin films with thicknesses less than 50 nm (<20 unit cells) are grown by pulsed laser deposition (PLD) onto (001) LaAlO3 (LAO) single crystal substrates. Phase-pure and smooth c-axis oriented Bi-2212 films with optimal oxygen doping, critical temperature Tc0 up to 86 K, and critical current ...
2306.14481v1
2023-07-12
Coexistence of Competing Microbial Strains under Twofold Environmental Variability and Demographic Fluctuations
Microbial populations generally evolve in volatile environments, under conditions fluctuating between harsh and mild, e.g. as the result of sudden changes in toxin concentration or nutrient abundance. Environmental variability thus shapes the long-time population dynamics, notably by influencing the ability of differen...
2307.06314v3
2023-07-31
Synthesis of possible room temperature superconductor LK-99:Pb$_9$Cu(PO$_4$)$_6$O
The quest for room-temperature superconductors has been teasing scientists and physicists, since its inception in 1911 itself. Several assertions have already been made about room temperature superconductivity but were never verified or reproduced across the labs. The cuprates were the earliest high transition temperat...
2307.16402v2
2023-10-11
Temperature-Dependent Collective Excitations in a Three-Dimensional Dirac System ZrTe$_{5}$
Zirconium pentatelluride (ZrTe$_{5}$), a system with a Dirac linear band across the Fermi level and anomalous transport features, has attracted considerable research interest for it is predicted to be located at the boundary between strong and weak topological insulators separated by a topological semimetal phase. Howe...
2310.07232v2
2023-10-19
Comparison of the Resistivities of Nanostructured Films Made from Silver, Copper-Silver and Copper Nanoparticle and Nanowire Suspensions
Spray deposition and inkjet printing of various nanostructures are emerging complementary methods for creating conductive coatings on different substrates. In comparison to established deposition techniques like vacuum metal coating and lithography-based metallization processes, spray deposition and inkjet printing ben...
2310.12506v1
2023-11-01
Active Noise Control Portable Device Design
While our world is filled with its own natural sounds that we can't resist enjoying, it is also chock-full of other sounds that can be irritating, this is noise. Noise not only influences the working efficiency but also the human's health. The problem of reducing noise is one of great importance and great difficulty. T...
2311.00535v1
2023-11-13
Superconductivity in trilayer nickelate La4Ni3O10 under pressure
Nickelate superconductors have attracted a great deal of attention over the past few decades due to their similar crystal and electronic structures with high-temperature cuprate superconductors. Here, we report the superconductivity in a pressurized Ruddlesden-Popper phase single crystal, La4Ni3O10 (n = 3), and its int...
2311.07423v2
2023-11-15
Quantification of cell contractile behavior based on non-destructive macroscopic measurement of tension forces on bioprinted hydrogel
Contraction assay based on surface measurement have been widely used to evaluate cell contractility in 3D models. This method is straightforward and requires no specific equipment, but it does not provide quantitative data about contraction forces generated by cells. We expanded this method with a new biomechanical mod...
2311.08773v1
2023-12-15
Plasma-enhanced atomic layer deposition of titanium nitride for superconducting devices
This study presents a comprehensive investigation into the exceptional superconducting attributes of titanium nitride (TiN) achieved through plasma-enhanced atomic layer deposition (PEALD) on both planar and intricate three-dimensional (3D) structures. We introduced an additional substrate biasing cycle to densify the ...
2312.09984v1
2023-12-19
On the role of Grain Boundary Character in the Stress Corrosion Cracking of Nanoporous Gold Thin Films
For its potential as a catalyst, nanoporous gold (NPG) prepared through dealloying of bulk Ag-Au alloys has been extensively investigated. NPG thin films can offer ease of handling, better tunability of the chemistry and microstructure of the nanoporous structure, and represent a more sustainable usage of scarce resour...
2312.12235v1
2024-02-26
Electronic phase transitions and superconductivity in ferroelectric Sn$_2$P$_2$Se$_6$ under pressure
Since there is both strong electron-phonon coupling during a ferroelectric/FE transition and superconducting/SC transition, it has been an important topic to explore superconductivity from the FE instability. Sn$_2$P$_2$Se$_6$ arouses broad attention due to its unique FE properties. Here, we reported the electronic pha...
2402.16427v1
2024-02-29
Anomalous frequency and temperature dependent scattering in the dilute metallic phase in lightly doped-SrTiO$_3$
The mechanism of superconductivity in materials with aborted ferroelectricity and the emergence of a dilute metallic phase in systems like doped-SrTiO$_3$ are outstanding issues in condensed matter physics. This dilute metal has features both similar and different to those found in the normal state of other unconventio...
2402.18767v1
2024-03-06
Crystal, ferromagnetism, and magnetoresistance with sign reversal in a EuAgP semiconductor
We synthesized the ferromagnetic EuAgP semiconductor and conducted a comprehensive study of its crystalline, magnetic, heat capacity, band gap, and magnetoresistance properties. Our investigation utilized a combination of X-ray diffraction, optical, and PPMS DynaCool measurements. EuAgP adopts a hexagonal structure wit...
2403.03650v1
2024-03-20
Optimizing Transparent Electrodes: Interplay of High Purity SWCNTs network and a Polymer
The discovery of transparent electrodes led to the development of optoelectronic devices such as OLEDs, LCDs, touchscreens, IR sensors, etc. Since ITO has many drawbacks in respect of its production cost and limited transparency in IR, carbon nanotubes (CNTs) have been a potential replacement for ITO due to their excep...
2403.13594v1
1996-10-01
Itinerant Antiferromagnetism in FeGe_2
FeGe_2, and lightly doped compounds based on it, have a Fermi surface driven instability which drive them into an incommensurate spin density wave state. Studies of the temperature and magnetic field dependence of the resistivity have been used to determine the magnetic phase diagram of the pure material which displays...
9610009v1
1998-05-25
Metal-insulator transition induced by 16O -18O oxygen isotope exchange in colossal negative magnetoresistance manganites
The effect of 16O-18O isotope exchange on the electric resistivity was studied for (La(1-y)Pr(y))0.7Ca0.3MnO3 ceramic samples. Depending on y, this mixed perovskite exhibited different types of low-temperature behavior ranging from ferromagnetic metal (FM) to charge ordered (CO) antiferromagnetic insulator. It was foun...
9805315v1
2001-04-13
Metal-insulator transition in 2D: a role of the upper Habbard band
To explain the main features of the metal-insulator transition (MIT) in 2D we suggest a simple model taking into account strongly localized states in the band tail of 2D conductivity band with a specific emphasize of a role of doubly-occupied states (upper Hubbard band). The metallic behavior of resistance is explained...
0104254v1
2001-05-31
Anomalous Nonlinear Microwave Response of Epitaxial YBa2Cu3O7-x Films on MgO
We have investigated the anomalous nonlinear microwave response of epitaxial electron-beam coevaporated YBa2Cu3O7-x films on MgO. The power and temperature dependent surface impedance and two-tone intermodulation distortion were measured in stripline resonators at several frequencies between 2.3 and 11.2 GHz and at tem...
0105613v1
2002-01-25
The influence of microstructures and crystalline defects on the superconductivity of MgB2
This work studies the influence of microstructures and crystalline defects on the superconductivity of MgB2, with the objective to improve its flux pinning. A MgB2 sample pellet that was hot isostatic pressed (HIPed) was found to have significantly increased critical current density (Jc) at high fields than its un-HIPe...
0201486v2
2004-04-19
Low temperature transport in granular metals
We investigate transport in a granular metallic system at large tunneling conductance between the grains. We show that at low temperatures, $T\leq g_T\delta $, where $\delta$ is the single mean energy level spacing in a grain, the coherent electron motion at large distances dominates the physics, contrary to the high t...
0404443v2
2004-10-21
Novel magnetic behavior of single crystalline Er2PdSi3
We report the results of ac and dc magnetic susceptibility (chi) and electrical resistivity (rho) measurements on the single crystals of Er2PdSi3, crystallizing in an AlB2-derived hexagonal structure, for two orientations H//[0001] and H//[2 -1 -1 0]. For H//[0001], there are apparently two magnetic transitions as reve...
0410532v1
2006-06-22
Metal-insulator transition in Nd$_{1-x}$Eu$_{x}$NiO$_{3}$ compounds
Polycrystalline Nd$_{1-x}$Eu$_{x}$NiO$_3$ ($0 \leq x \leq 0.5$) compounds were synthesized in order to investigate the character of the metal-insulator (MI) phase transition in this series. Samples were prepared through the sol-gel route and subjected to heat treatments at $\sim$1000 $^\circ$C under oxygen pressures as...
0606573v1
2007-03-21
Dynamics of the Magnetic Flux Trapped in Fractal Clusters of a Normal Phase in Percolative Superconductors
The effect of the fractal clusters of a normal phase, which act as pinning centers, on the dynamics of magnetic flux in percolative type-II superconductor is considered. The main features of these clusters are studied in detail: the cluster statistics is analyzed; the fractal dimension of their boundary is estimated; t...
0703541v1
2007-03-27
Diffusion and activation of n-type dopants in germanium
The diffusion and activation of $n$-type impurities (P and As) implanted into $p$-type Ge(100) substrates were examined under various dose and annealing conditions. The secondary ion mass spectrometry profiles of chemical concentrations indicated the existence of a sufficiently high number of impurities with increasing...
0703708v3
2008-10-14
Superconductivity in Fluorine-Arsenide Sr_{1-x}La_xFeAsF
Since the discovery of superconductivity\cite{1} at 26 K in oxy-pnictide $LaFeAsO_{1-x}F_x$, enormous interests have been stimulated in the fields of condensed matter physics and material sciences. Among the five different structures in this broad type of superconductors\cite{2,3,4,5,6}, the ZrCuSiAs structure has rece...
0810.2531v3
2009-07-09
Annular Spin-Transfer Memory Element
An annular magnetic memory that uses a spin-polarized current to switch the magnetization direction or helicity of a magnetic region is proposed. The device has magnetic materials in the shape of a ring (1 to 5 nm in thickness, 20 to 250 nm in mean radius and 8 to 100 nm in width), comprising a reference magnetic layer...
0907.1600v1
2009-09-16
Band structure engineering of epitaxial graphene on SiC by molecular doping
Epitaxial graphene on SiC(0001) suffers from strong intrinsic n-type doping. We demonstrate that the excess negative charge can be fully compensated by non-covalently functionalizing graphene with the strong electron acceptor tetrafluorotetracyanoquinodimethane (F4-TCNQ). Charge neutrality can be reached in monolayer g...
0909.2966v2
2010-01-07
Anisotropic Connectivity and its Influence on Critical Current Densities, Irreversibility Fields, and Flux Creep in In-Situ-Processed MgB2 Strands
The anisotropy of the critical current density (Jc) and its influence on measurement of irreversibility field (Birr) has been investigated for high quality, in-situ MgB2 strands. Comparison of transport and magnetization measurements has revealed the onset of a regime where large differences exist between transport and...
1001.1030v1
2010-04-21
Determination of the intrinsic ferroelectric polarization in orthorhombic HoMnO3
Whether large ferroelectric polarization P exists in the orthorhombic HoMnO3 with the E-type antiferromagnetic spin ordering or not remains as one of unresolved, challenging issues in the physics of multiferroics. The issue is closely linked to an intriguing experimental difficulty for determining P of polycrystalline ...
1004.3643v1
2010-07-26
Python Regius (Ball Python) shed skin: Biomimetic analogue for function-targeted design of tribo-surfaces
A major concern in designing tribo-systems is to minimize friction, save energy, and to reduce wear. Satisfying these requirements depends on the integrity of the rubbing surface and its suitability to sliding conditions. As such, designers currently focus on constructing surfaces that are an integral part of the funct...
1007.4419v1
2010-11-09
Phase diagram of iron-arsenide superconductors Ca(Fe1-xCox)2As2 (0 <= x <= 0.2)
Platelet-like single crystals of the Ca(Fe1-xCox)2As2 series having lateral dimensions up to 15 mm and thickness up to 0.5 mm were obtained from the high temperature solution growth technique using Sn flux. Upon Co doping, the c-axis of the tetragonal unit cell decreases, while the a-axis shows a less significant varia...
1011.2085v1
2011-08-17
Impact of Protostellar Outflow on Star Formation: Effects of Initial Cloud Mass
Star formation efficiency controlled by the protostellar outflow in a single cloud core is investigated by three-dimensional resistive MHD simulations. Starting from the prestellar cloud core, the star formation process is calculated until the end of the main accretion phase. In the calculations, the mass of the preste...
1108.3564v1
2012-05-02
Negative thermal expansion and antiferromagnetism in the actinide oxypnictide NpFeAsO
A neptunium analogue of the LaFeAsO tetragonal layered compound has been synthesized and characterized by a variety of experimental techniques. The occurrence of long-range magnetic order below a critical temperature T_N = 57 K is suggested by anomalies in the temperature-dependent magnetic susceptibility, electrical r...
1205.0438v1
2012-09-13
Magnetic phase transitions in single crystals of the chiral helimagnet Cr1/3NbS2
The chiral helimagnet Cr1/3NbS2 has been investigated by magnetic, transport and thermal properties measurements on single crystals and by first principles electronic structure calculations. From the measured field and temperature dependence of the magnetization for fields applied perpendicular to the c axis, the magne...
1209.2783v1
2013-04-15
Non-Fermi liquids and the Wiedemann-Franz law
A general discussion of the ratio of thermal and electrical conductivities in non-Fermi liquid metals is given. In metals with sharp Drude peaks, the relevant physics is correctly organized around the slow relaxation of almost-conserved momenta. While in Fermi liquids both currents and momenta relax slowly, due to the ...
1304.4249v3
2014-05-15
Anomalous frequency and temperature dependent scattering and Hund's coupling in the almost quantum critical heavy fermion system CeFe$_2$Ge$_2$
We present THz range optical conductivity data of a thin film of the near quantum critical heavy fermion compound CeFe$_2$Ge$_2$. Our complex conductivity measurements find a deviation from conventional Drude-like transport in a temperature range previously reported to exhibit unconventional behavior. We calculate the ...
1405.4007v3
2014-05-23
Growth and characterization of heteroepitaxial La-substituted BaSnO$_3$ films on SrTiO$_3$ (001) and SmScO$_3$ (110) substrates
Heteroepitaxial growth of BaSnO$_3$ (BSO) and Ba$_{1-x}$La$_x$SnO$_3$ (x = 7 %) (LBSO) thin films on different perovskite single crystal (SrTiO$_3$ (001) and SmScO$_3$ (110)) substrates has been achieved by Pulsed Laser Deposition (PLD) under optimized deposition conditions. X-ray diffraction measurements indicate that...
1405.6233v1
2014-05-31
Scale-Invariant Dissipationless Chiral Transport in Magnetic Topological Insulators beyond the Two-Dimensional Limit
We investigate the quantum anomalous Hall Effect (QAHE) and related chiral transport in the millimeter-size (Cr0.12Bi0.26Sb0.62)2Te3 films. With high sample quality and robust magnetism at low temperatures, the quantized Hall conductance of e2/h is found to persist even when the film thickness is beyond the two-dimensi...
1406.0106v2
2014-09-11
High performance solar cells based on graphene-GaAs heterostructures
The honeycomb connection of carbon atoms by covalent bonds in a macroscopic two-dimensional scale leads to fascinating graphene and solar cell based on graphene/silicon Schottky diode has been widely studied. For solar cell applications, GaAs is superior to silicon as it has a direct band gap of 1.42 eV and its electro...
1409.3500v3
2014-10-13
Breakdown of Three-dimensional Dirac Semimetal State in pressurized Cd3As2
We report the first observation of a pressure-induced breakdown of the 3D-DSM state in Cd3As2, evidenced by a series of in-situ high-pressure synchrotron X-ray diffraction (XRD) and single crystal transport measurements. We find that Cd3As2 undergoes a structural phase transition from a metallic tetragonal (T) phase in...
1410.3213v4
2014-11-13
Analysis of viscoelastic soft dielectric elastomer generators operating in an electrical circuit
A predicting model for soft Dielectric Elastomer Generators (DEGs) must consider a realistic model of the electromechanical behaviour of the elastomer filling, the variable capacitor and of the electrical circuit connecting all elements of the device. In this paper such an objective is achieved by proposing a complete ...
1411.3613v2
2014-11-28
Growth control of the oxidation state in vanadium oxide thin films
Precise control of the chemical valence or oxidation state of vanadium in vanadium oxide thin films is highly desirable for not only fundamental research, but also technological applications that utilize the subtle change in the physical properties originating from the metal- insulator transition (MIT) near room temper...
1411.7922v1
2014-12-05
Effects of Oxygen Adsorption on the Surface State of Epitaxial Silicene on Ag(111)
Epitaxial silicene, which is one single layer of silicon atoms packed in a honeycomb structure, demonstrates a strong interaction with the substrate that dramatically affects its electronic structure. The role of electronic coupling in the chemical reactivity between the silicene and the substrate is still unclear so f...
1412.1887v1
2015-02-10
Ultrafast dynamic conductivity and scattering rate saturation of photoexcited charge carriers in silicon investigated with a midinfrared continuum probe
We employ ultra-broadband terahertz-midinfrared probe pulses to characterize the optical response of photoinduced charge-carrier plasmas in high-resistivity silicon in a reflection geometry, over a wide range of excitation densities (10^{15}-10^{19} cm^{-3}) at room temperature. In contrast to conventional terahertz sp...
1502.02829v1
2015-03-03
Construction of force measuring optical tweezers instrumentation and investigations of biophysical properties of bacterial adhesion organelles
Optical tweezers are a technique in which microscopic-sized particles, including living cells and bacteria, can be non-intrusively trapped with high accuracy solely using focused light. The technique has therefore become a powerful tool in the field of biophysics. Optical tweezers thereby provide outstanding manipulati...
1503.00881v1
2015-03-30
Microbranching in mode-I fracture using large scale simulations of amorphous and perturbed lattice models
We study the high-velocity regime mode-I fracture instability when small microbranches start to appear near the main crack, using large scale simulations. Some of the features of those microbranches have been reproduced qualitatively in smaller scale studies (using ${\cal O}(10^4)$ atoms) on both a model of an amorphou...
1503.08616v2
2016-04-12
An invisible non-volatile solid-state memory
Information technologies require entangling data stability with encryption for a next generation of secure data storage. Current magnetic memories, ranging from low-density stripes up to high-density hard drives, can ultimately be detected using routinely available probes or manipulated by external magnetic perturbatio...
1604.03383v2
2016-05-19
Robust two-dimensional superconductivity and vortex system in Bi2Te3/FeTe heterostructures
The discovery of two-dimensional superconductivity in Bi2Te3/FeTe heterostructure provides a new platform for the search of Majorana fermions in condensed matter systems. Since Majorana fermions are expected to reside at the core of the vortices, a close examination of the vortex dynamics in superconducting interface i...
1605.05903v1
2016-07-06
Chiral anomaly from strain-induced gauge fields in Dirac and Weyl semimetals
Dirac and Weyl semimetals form an ideal platform for testing ideas developed in high energy physics to describe massless relativistic particles. One such quintessentially field-theoretic idea of chiral anomaly already resulted in the prediction and subsequent observation of the pronounced negative magnetoresistance in ...
1607.01810v2
2016-11-17
Interfacial thermal conductance in graphene/black phosphorus heterogeneous structures
Graphene, as a passivation layer, can be used to protect the black phosphorus from the chemical reaction with surrounding oxygen and water. However, black phosphorus and graphene heterostructures have low efficiency of heat dissipation due to its intrinsic high thermal resistance at the interfaces. The accumulated ener...
1611.05598v1
2017-06-08
Electronic and phonon excitations in α-RuCl$_3$
We report on THz, infrared reflectivity and transmission experiments for wave numbers from 10 to 8000 cm$^{-1}$ ($\sim$ 1 meV - 1 eV) and for temperatures from 5 to 295 K on the Kitaev candidate material {\alpha}-RuCl$_3$. As reported earlier, the compound under investigation passes through a first-order structural pha...
1706.02724v2