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Transport properties of CeO0.85F0.15SbS2 and undoped CeOSbS2 under high pressure were investigated experimentally and theoretically. Electrical resistivity measurements of the CeO0.85F0.15SbS2 single crystals were performed under various high pressures using a diamond anvil cell with boron-doped diamond electrodes. The samples showed the insulator to metal transition by applying a high pressure up to 30-40 GPa. On the other hand, the undoped CeOSbS2 showed almost the same transport property with the F-doped sample under high pressure. The valence state analysis using X-ray photoelectron spectroscopy revealed a simple valence state of Ce3+ in CeO0.85F0.15SbS2 and mixed valence state between Ce3+ and Ce4+ in undoped CeOSbS2. The valence fluctuation in Ce carried out the comparable transport nature in both samples. A band calculation suggests that the undoped CeOSbS2 could be metallic under high pressure of 30 GPa in accordance with the experimental results. A superior thermoelectric property of power factor in CeOSbS2 was estimated under high pressure around 20 GPa in comparison with that of ambient pressure. [ABSTRACT FROM AUTHOR]

Transport properties of CeO0.85F0.15SbS2 and undoped CeOSbS2 under high pressure were investigated experimentally and theoretically. Electrical resistivity measurements of the CeO0.85F0.15SbS2 single crystals were performed under various high pressures using a diamond anvil cell with boron-doped diamond electrodes. The samples showed the insulator to metal transition by applying a high pressure up to 30-40 GPa. On the other hand, the undoped CeOSbS2 showed almost the same transport property with the F-doped sample under high pressure. The valence state analysis using X-ray photoelectron spectroscopy revealed a simple valence state of Ce3+ in CeO0.85F0.15SbS2 and mixed valence state between Ce3+ and Ce4+ in undoped CeOSbS2. The valence fluctuation in Ce carried out the comparable transport nature in both samples. A band calculation suggests that the undoped CeOSbS2 could be metallic under high pressure of 30 GPa in accordance with the experimental results. A superior thermoelectric property of power factor in CeOSbS2 was estimated under high pressure around 20 GPa in comparison with that of ambient pressure. [ABSTRACT FROM AUTHOR]

Topological insulators (TIs) represent a new state of matter possessing an attractive surface spin texture with possible applications in quantum computation and spintronics. The growth of prototypical TIs such as Bi 2 Te 3 and Bi 2 Se 3 still remains a major challenge, because of vacancies and defects leading to an unintentional doping of the crystals creating a parallel conduction channel in the bulk. Here, we synthesized the Bi 2 Te 2.15 Se 0.85 (BTS) TI using a modified Bridgeman technique. Magnetotransport studies at different angles and temperatures of the device made on thin (BTS) flakes reveal the 2D nature of the weak antilocalization signal and surface dominated transport properties at low temperatures. [ABSTRACT FROM AUTHOR]

We have deposited LaNiO3 thin films on LaAlO3 (001), SrTiO3 (001), and Si (001) substrates using the pulsed laser deposition technique. Depositions were carried out at various substrate temperatures ranging from 0 to 800 °C. The effects of lattice mismatch and structural disorder on the transport properties of films deposited on various substrates and at different substrate temperatures are reported. X-ray diffraction confirms a highly c-axis oriented growth of LaNiO3 films on all the substrates at substrate temperatures of 600 and 800 °C, while at lower substrate temperatures deposited films are amorphous. Emergence of a new Raman mode indicates symmetry lowering in all the deposited crystalline films. Hardening of the Eg(3) (∼400 cm−1) mode is also observed with the rise of in-plane compressive strain. Resistivity curves for films on Si show a semiconducting behaviour and follow a variable range hopping mechanism. Crystalline films on LaAlO3 and SrTiO3 exhibit a metallic character along with a low-temperature resistivity upturn, which is attributed to the contribution of self-localization to resistivity at low temperatures as indicated by magnetotransport measurements. [ABSTRACT FROM AUTHOR]

The transport properties of the thiospinel CuCrTiS4 have been investigated in detail, focusing on the possible interplay between charges and spins, and its consequence on transport, and more specifically on the thermoelectric properties. The chemical homogeneity of a CuCrTiS4 polycrystalline sample synthesized by a direct reaction of the constitutive elements has been carefully probed by X-ray diffraction and transmission electron microscopy techniques. This thiospinel exhibits below 75 K, in its paramagnetic regime, a variable range hopping (VRH) conduction, associated with a giant magnetoresistance (MR), which persists below the spin-glass transition temperature at 8 K, reaching -95% in 9 T at 5 K. All the MR data can be rescaled as a function of H/T and described using a Brillouin function with S = 3/2. This demonstrates that the paramagnetic fluctuations strongly impact the transport properties, and this is confirmed by the Seebeck coefficient which depends on the magnetic field at low temperature, with a large negative magnetothermopower (MTEP) effect of -26% at 20 K, i.e., the thermopower is reduced as the spin alignment reduces the spin entropy. This first report of MTEP in CuCrTiS4 shows that this thiospinel behaves rather similarly to strongly correlated oxides, with MR and MTEP enhanced in the case of VRH transport with paramagnetic spins, such as in cobalt misfits or colossal MR manganites. [ABSTRACT FROM AUTHOR]

In this work, we investigate the electronic transport properties of a graphene allotrope composed of 5–6-7 carbon aromatic rings called phagraphene and compare with the results of the transition-voltage spectroscopy (TVS) and propose the behavior at low voltage characteristic of a topological insulator. Phagraphene properties were compared to those of graphene in a zigzag nanoribbon configuration, zigzag graphene vs zigzag phagraphene nanoribbon (zzGNR and zzPGNR). The molecular geometry and the electronic properties were calculated by density functional theory (DFT) without spin, and the electronic transport and TVS were obtained by means of DFT combined with non-equilibrium Green´s function when we couple the optimized geometry of zzGNR and zzPGNR to the leads (left and right), forming the molecular junction that will be subjected to the action of an external bias voltage (Ve) to generate the molecular device. The results exhibit (i) a metal-insulator transition when Ve is increased until Ve = 1.4 V which corresponds to the nonlinear region (resonance), showing the field effect transistor behaviour for zzGNR junctions; and (ii) two nonlinear regions (two negative differential resistances), showing a resonant tunnel diode behaviour with two operation windows (Ve = 0.5 V and Ve = 1.7 V) for the zzPGNR junction. In addition, the zzPGNR junction exhibits topological insulator characteristics upon introducing topological defects such as pentagons and heptagons in the hexagonal lattice of graphene, and when Ve = 1.7 V, there occurs a topological insulator-metal transition that can be seen in the behaviour of the density of states, transmittance, and frontier molecular orbitals with Ve. [ABSTRACT FROM AUTHOR]

Recently, single-molecule manipulation techniques in micro- and nanofluidic channels have attracted significant attention. To precisely control the transport velocity, the dynamics of the surrounding liquid must be understood in addition to the behavior of the target particles. Some unknowns about interactions between electrolyte ions and solvents remain to be clarified from a microscopic viewpoint. Herein, we propose a technique to generate a liquid flow driven by ion transport phenomena, the so-called electrohydrodynamic (EHD) flow, where electrolyte ions are dialyzed using a cation-exchange membrane. With this method, it is possible to apply an electric body force in liquids, which is different from electroosmotic flows that are limited to ion transport in electric double layers, and is expected to be a good candidate for detailed control of liquid flows in micro- and nanofluidic channels. To collect basic design data based on the knowledge of microscopic fluid dynamics of the present technique, a mathematical model of an EHD flow dragged by electrical carriers in an ionic current is developed and results are compared with experimental data. In our experiments, EHD flows are efficiently driven by applied electric fields in a cation dominant current. To induce such an EHD flow, the externally applied electric potential can be drastically reduced to 2.0 V in comparison with previous methods because we do not need an excessively high voltage to inject electrical charges into liquids. This method enables us to induce EHD flows in aqueous solutions and is expected to open the door to low-voltage driven liquid flow control. [ABSTRACT FROM AUTHOR]

A highly accurate, consistent set of ab initio interaction potentials is obtained for the title systems at the coupled cluster with singles, doubles, and non-iterative triples level of theory with extrapolation to the complete basis set limit. These potentials are shown to be more reliable than the previous potentials based on their long-range behavior, equilibrium properties, collision cross sections, and transport properties. [ABSTRACT FROM AUTHOR]

Three keynote thermophysical and transport properties of ³He and 4He, namely, the second virial coefficient, the shear viscosity, and the thermal conductivity, are reported for the "extended Dirac bubble potential" (EDbp), a novel model for He--He [M. Chrysos, J. Chem. Phys. 146, 024106 (2017)]. Comparisons with the experiment as well as with potentials with a proven track record and with the oversimplified Dbp are being made in the range 0.1-500 K to analyze the performance of the EDbp, which is shown here to emerge as a promising analytic model for He--He. A flowchart of how to treat the "buffer" in scattering cross section measurements is designed and conducted, offering a route to EDbp optimization. An impressive consistency with state-of-the-art calculations (which is just striking for such a simple analytic model) is found, essentially thanks to the performance of the phase-shift expression cot ... A Multimedia view of δl(k, rc) versus k and rc is part of the material presented in this article. Data for the "best" rc(k) is given as a supplementary material. [ABSTRACT FROM AUTHOR]

The current study aims to investigate influence of w/cm ratio, cementitious materials content and supplementary cementitious materials on the transport properties of concrete and chloride-induced corrosion rate of reinforcement. To do this, several mixes are designed with and without silica fume and natural zeolite as supplementary cementitious materials, w/cm of 0.4 and 0.5, and cementitious materials contents of 325 and 400 kg/m3. These mixes are subjected to evaluation of compressive strength, transport properties (i.e. absorption, water penetration depth and rapid chloride penetration test), and corrosion rate measurement through Potentiodynamic test and electrochemical measurements. The results of this study reveal that there is not strong correlation between corrosion rate of reinforcement and the measured strength and transport properties. The corrosion rate of reinforcement significantly decreased through reduction of water-tocementitious materials ratio and use of supplementary cementitious materials; of which w/cm showed a more considerable influence. Increase in cement content, however, increased the transportation of water and chloride into the concrete and thus increased the corrosion rate of reinforcement. [ABSTRACT FROM AUTHOR]

Defect structure and chemical diffusion in the (Co,Cr,Fe,Mn,Ni) 3 O 4 high entropy oxide is investigated. The material is synthesized by means of a solid-state reaction, through sintering mixture of composing oxides at 1273 K for 20 h. Presence of the single-phase, spinel-structured high entropy solid solution is confirmed with the use of X-ray diffraction method and scanning electron microscopy. Good thermal stability of the material is documented up to 1273 K. Modified marker experiment allows concluding that defects form predominantly in the oxygen sublattice. Based on thermogravimetric studies, general formula of (Co,Cr,Fe,Mn,Ni) 3 O 4±y is established, with the defect inversion phenomenon (i.e. change of the dominating type of defects from oxygen vacancies to interstitial oxygen) likely to occur at high oxygen partial pressures (p O 2 ). Chemical diffusion coefficient is calculated, based on the measured reequilibration kinetics, showing a very strong dependence on p O 2 and relatively small values under low oxygen pressures. [ABSTRACT FROM AUTHOR]

• The La 1–x Ba x YbO 3– δ (LBY) materials were successfully synthesized. • Ba-doping results in a deterioration of sintering behaviour of LBY. • Transport properties of LBY were studied by AC and DC conductivity measurements. • Bulk conductivity changes more sharply than the grain boundary one with x variation. • La 0.97 Ba 0.03 YbO 3– δ exhibits the highest conductivity values. The effective operation of protonic ceramic electrochemical cells requires the design of electrolytes having not only high ionic conductivity, but also excellent stability with respect to carbonisation. In the present work, the La-based oxides (La 1–x Ba x YbO 3– δ, 0.03 ≤ x ≤ 0.10) are proposed as a possible alternative to the convenient Ba(Ce,Zr)O 3 -based electrolytes due to their high chemical stability. It was discovered that Ba-doping results in a deterioration of sintering behaviour; as a result, the relative density decreases and open porosity appears (for x = 0.10). A thorough analysis of transport properties by means of AC and DC measurement techniques enables a selection of the La 0.97 Ba 0.03 YbO 3– δ sample, which demonstrates the highest conductivity compared with those samples where x = 0.5 and 0.10. Due to its excellent densification behaviour, stability and ionic conductivity, La 0.97 Ba 0.03 YbO 3– δ can be considered as a promising proton-conducting electrolyte in the La-based family. [ABSTRACT FROM AUTHOR]

This study proposes in situ optical microspectroscopy as a means for the investigation of particle growth and metal transport in nanocomposite systems based on the temperature- and time-dependent optical response of the material. The technique has been successfully employed for the real-time monitoring of the growth of Ag nanoparticles (NPs) in SiO2 films deposited on soda-lime glass during thermal processing in nitrogen atmosphere. By fitting the surface plasmon resonance (SPR) profiles with spectra calculated by Mie theory in the quasi-static regime, the time variation in effective Ag particle size was determined and subsequently analyzed in the context of crystal growth theory. The Ag NPs were indicated to grow first through a diffusion-based process and subsequently via Ostwald ripening. The experimental determination of the activation energies associated with each one of the particle growth mechanisms was carried out based on the time evolution of the SPR of Ag NPs. Arrhenius-type analyses of a set of time-dependent isotherms allowed for estimating the activation energies at 2.3 eV for the diffusion-based growth and 2.8 eV for the ripening stage. [ABSTRACT FROM AUTHOR]

The electronic structure and transport properties of the Cp2BzM2 (M = Sc, Ti, and V) tripledeckers are studied by spin polarized density functional theory and nonequilibrium Green's function method considering high-spin and low-spin states. Total energy calculations show that the sandwich structured Cp2BzSc2 exists in a singlet state with no local magnetic moment on the Sc atoms. Cp2BzTi2 in triplet state exists as a distorted tripledecker and is more stable than singlet and quintet states. Cp2BzV2 stabilizes in the quintet state with a spin density of 2.4 on each vanadium atom. Hund's coupling plays a vital role in stabilizing the higher multiplets in case of titanium and vanadium clusters. In bigger clusters like Cp3Bz2M4, Sc multidecker has one unpaired spin, Ti multidecker has five unpaired spins, and V multidecker has seven unpaired spins in total. Spin polarized electronic transport is found for all states of vanadium tripledecker and one state of the titanium tripledecker when connected to a gold two probe junction. Moderate to high-spin filter efficiencies are calculated for these states. Cp2BzSc2 shows spin-independent electronic transport for all electronic states when introduced in the gold two probe junction. Current versus voltage curves are reported for selected clusters in the two probe setup. [ABSTRACT FROM AUTHOR]

We present a technique that retrieves the thermal diffusivity of metallic samples in a two-dimensional map with micrometer resolution. The technique uses a photothermal method based on the deflection of a probe beam after heating the surface with a modulated pump. After adequate calibration, the time delay between the pump modulation and the deflection modulation provides direct information on the local thermal diffusivity. The calibration is carried out by measuring the frequency dependence of the deflection signal at several sample locations. The capabilities of the technique are illustrated with the measurement of a cross section of a surface treated steel sample. [ABSTRACT FROM AUTHOR]

We report on the magnetotransport properties of 100 nm wide parabolic quantum wells and observe an enhancement of the Hall resistance in one sample but not the other. This phenomenon is likely related to the effective thickness of the electronic slab. We also observe a parabolic negative magnetoresistance originating from electron-electron interactions when only one subband is occupied in one of the samples. The interaction correction to the Drude conductivity is extracted using two methods. We find that the extracted interaction correction increases with increasing tilted angle, for which two possible explanations are given. [ABSTRACT FROM AUTHOR]

Electronic transmission through a metal-molecule-metal system is calculated by employing a Green’s function formalism in the scattering based scheme. Self-energy models representing the bulk and the potential bias are used to describe electron transport through the molecular system. Different self-energies can be defined by varying the partition between device and bulk regions of the metal-molecule-metal model system. In addition, the self-energies are calculated with different representations of the bulk through its Green’s function. In this work, the dependence of the calculated transmission on varying the self-energy subspaces is benchmarked. The calculated transmission is monitored with respect to the different choices defining the self-energy model. In this report, we focus on one-dimensional model systems with electronic structures calculated at the density functional level of theory. [ABSTRACT FROM AUTHOR]

Spin-polarized electronic and transport properties of carbon atomic chains are investigated when they are capped with magnetic transition-metal (TM) atoms like Cr or Co. The magnetic ground state of the TM-Cn-TM chains alternates between the ferromagnetic (F) and antiferromagnetic (AF) spin configurations as a function of n. In view of the nanoscale spintronic device applications the desirable AF state is obtained for only even-n chains with Cr; conversely only odd-n chains with Co have AF ground states. When connected to appropriate metallic electrodes these atomic chains display a strong spin-valve effect. Analysis of structural, electronic, and magnetic properties of these atomic chains, as well as the indirect exchange coupling of the TM atoms through non-magnetic carbon atoms are presented. [ABSTRACT FROM AUTHOR]

We fabricate field-effect transistors (FETs) by depositing a regioregular poly(3-hexylthiophene) (RR-P3HT) active layer via different preparation methods. The solvent used in the polymer film deposition and the deposition technique determine the film microstructure, which ranges from amorphous or granular films to a well-defined fibrillar texture. The crystalline ordering of RR-P3HT into fibrillar structures appears to lead to optimal FET performances, suggesting that fibrils act as efficient “conduits” for the charge carrier transport. Treating the silicon oxide gate insulator with hexamethyldisilazane enhanced the FET performance. [ABSTRACT FROM AUTHOR]

ZnSb is a favourable eco-friendly, earth abundant SIand low cost thermoelectric material. We herein report a feasible approach to improve the thermoelectric performance of ZnSb by compositing with hydrothermally synthesized Sb. A series of ZnSb/Sb composites was fabricated by mixing the host material ZnSb and hydrothermally synthesized Sb followed by consolidation using cold pressing and evacuating-and-encapsulating sintering at 530 °C for 3 h. As compared to the host ZnSb, both the electrical resistivity and thermopower decrease, while both the power factor and thermal conductivity increase upon compositing with Sb. The bipolar transport of ZnSb is suppressed at temperatures up to 600 K. As a result, the ZnSb-Sb composite with 4 wt.% of hydrothermally synthesized Sb has a zT = 1.18 at 600 K, which is one of the highest values for ZnSb-based material and is about 46% enhancement as compared to the host ZnSb having zT = 0.81 at 600 K. [ABSTRACT FROM AUTHOR]

The defect structure and chemical diffusion in the (Co,Cu,Mg,Ni,Zn)O high entropy oxide were investigated. The material was synthesized in a form of pellets by means of a solid-state reaction, through sintering the mixture of composing oxides at 1273 K for 20 h, followed by the air quenching. The presence of the single-phase, high entropy solid solution structure was confirmed with the use of SEM + EDS and XRD methods and later confirmed after each of the experimental steps. The modification of the standard marker experiment was applied, to determine the predominantly disordered sublattice, which turned out to be the anionic one. The nonstoichiometry and its dependence on the oxygen partial pressure were investigated by means of the thermogravimetric method. The results allowed establishing the (Co,Cu,Mg,Ni,Zn)O 1- y general formula, with values of y reaching values as high as 0.07 under low oxygen partial pressures. The non-logarithmic character of the obtained pressure dependence suggests the presence of a complex structure of interacting point defects. The chemical diffusion coefficient was also determined, based on the measured re-equilibration kinetics. The obtained values of diffusivity are within the range typical for the transition metal oxides, do not confirm the presence of the sluggish diffusion effect in high entropy oxides. The established strong dependence of the chemical diffusion coefficient on the p (O 2), further confirms the presence of the complex defect structure. [ABSTRACT FROM AUTHOR]

Polycrystalline samples of Bi 1 − x LaxFeO3 [ x = 0. 5 , 0.6, 0.7 and 0.8] were synthesized through high temperature solid state reaction method. The structural studies of the compounds were done using X-ray diffraction technique. Dielectric constant and dielectric loss were studied for various frequencies (100 Hz–104 Hz) at different temperatures. The temperature-dependent non-Debye type relaxation process was suggested in the materials from the analysis of frequency-dependent electrical data at different temperatures. Temperature dependence of dc and ac conductivity at various frequencies showed negative temperature coefficient of resistance (NTCR) behavior. The frequency dependence of ac conductivity at different temperatures obeyed Jonscher's universal power law. The temperature dependence of dc and ac conductivity was fitted to Arrhenius equation. The activation energies at different temperature ranges were calculated to know the charge species involved in the conduction process. [ABSTRACT FROM AUTHOR]

PbTiO3 nanorods with tetragonal phase were synthesized by hydrothermal method and heat treatment, and temperature-dependent electrical transport properties of individual PbTiO3 nanorod were investigated. The results show that the conductivities of PbTiO3 nanorods are gradually enhanced with temperature increasing from 77.4 to 295 K, and exhibit the typical nonlinear I–V characteristics. The barrier height between Au electrode and nanorod is reduced from 0.137 to 0.088 eV with increasing bias from 0.2 to 1 V. The corresponding values of thermal activation energies are 0.172 and 0.06 eV below the conduction band for 180–295 and 77.4–180 K, respectively. This semiconductor-like behavior may result from the larger number of surface defects or localized states in the amorphorized PbTiO3. [ABSTRACT FROM AUTHOR]

• Enhanced efficiency of TiO 2 DSSC by demagnetization fields. • Enhanced recombination time due to stray fields. • Evidence for stray fields using magnetic force microscopy and micromagnetic simulations. • Realization of more absorption of the light through transfer matrix modelling. We report on the effect of demagnetizing fields due to magnetite (Fe 3 O 4) nanoparticles (NPs) on the efficiency of TiO 2 based dye sensitized solar cells (DSSC). The addition of Fe 3 O 4 NPs into the photoanode enhanced the power conversion efficiency of DSSC. This may be attributed to the magnetic field effect induced by the demagnetizing field produced by the magnetite NPs, which is evident from our micromagnetic simulation. Essentially, such a stray field would induce additional force on the electron motion and thereby enhancing the recombination time of these charge carriers. Enhancement in recombination time is directly evidenced by the increase in short circuit current density. In addition, we have carried out an electrochemical impedance spectroscopy (EIS) study to probe the mechanism of charge transport within the DSSC device. Quenching of intensity in phosphorescence data indeed infer a decrease in recombination rate. We calculated the value of demagnetization energy from NPs with micromagnetic simulations. Absorbed energy density of 's' and 'p' polarized incident light estimated using transfer matrix model. [ABSTRACT FROM AUTHOR]

Diluted magnetic semiconductors (DMSs), having interesting magnetic/transport properties, are currently being explored in photocatalytic application as well. This report presents photocatalytic and low temperature magnetic/transport study of chemically synthesized 3-5 nm sized cubic Zn1-xCuxS (0 ≤ x ≤ 0.04) DMS nanoparticles. Both studies have their own importance, former relates to dye degradation, while later attempts to understand origin of magnetic behavior in DMSs (which is still debatable). As a photocatalyst, Cu doped ZnS NPs showed enhanced degradation-efficiency for methylene blue dye. Magnetization study showed enhanced magnetic moment in Cu doped samples, which in the low temperature regime got further enhanced and was understood due to defect induced ferromagnetism. Low temperature transport study showed the decrease in resistivity of the Cu doped samples and was understood in terms of defects states created due to doping of the Cu ions and governed by conduction mechanism, namely thermal activation and variable range hopping. [ABSTRACT FROM AUTHOR]

Abstract Short but intense laser pulses may produce the high surface temperatures of metal or semiconductor targets exceeding the corresponding melting points. Hydrodynamic modeling of nano-scale fragmentation of a thin surface layer is feasible if the reflectivity and heat conductivity coefficients, usually obtained from experiments, are available. However, for such materials as silicon and titanium the experimental electric resistivity and heat conductivity are available only in narrow temperature ranges above the melting points. On the other hand, the heated surface layer keeps its initial density during a short two-temperature stage because the timescales of both femtosecond laser heating and electron-ion energy exchange are too short for material expansion. The short-lived high-temperature states of materials in this layer are also challenging for experimental study with techniques such as electrical explosion of wires or films. We perform accurate simulations of several materials in such states, including aluminum, copper, gold, silicon, and titanium, at the corresponding equilibrium volumes at room temperature and along their liquid-vapor coexistence curves using both classical and quantum molecular dynamics. The corresponding electron transport properties calculated by the Kubo-Greenwood theory are presented. Highlights • Transport coefficients of metals and Si are obtained for ns and fs laser heating. • Role of e-e collisions in transport coefficients are investigated for noble metals. • Heat conductivity for copper is converged if cell size contains 200 atoms. [ABSTRACT FROM AUTHOR]

In order to evaluate the influence of acoustic phonon scattering on electron mobility in β -Ga2O3, electronic structure and transport properties were analyzed under the frame of deformation potential and relaxation time approximation. First-principles calculations were carried out, to calculate band structure, density of states, effective mass, and analyzed transport properties in intrinsic and metal doped β -Ga2O3. The electron mobility caused by acoustic phonon (AC) scattering mechanism was taken into consideration. The result suggested that electron mobility is determined by deformation potential and effective mass, and mainly depend on deformation potential parameter. Furthermore, the calculated value of electron mobility in most metal atom doped structures have a great increase compared with pristine β -Ga2O3, and electron mobility shown prominent anisotropy in metal doped Ga2O3, especially electron mobility along [100] direction in copper doped β -Ga2O3 is an order of magnitude larger than that of intrinsic β -Ga2O3. This work confirmed the AC scattering is a non-negligible mechanism which limit the electron mobility in Ga2O3 system, and will provide a favorable reference for the further application of β -Ga2O3 in electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Abstract Comparitive analysis of the corrosion resistance of H32 5052 Al alloy and galvanized mild steel lap joints fabricated by a) Metal Inert Gas (MIG) Welding-brazing and b) Cold metal transfer (CMT) was done by keeping wire feed rate and welding speed constant. The weld interfaces of 5052 Al and mild steel were characterized using Field emission scanning electron microscopy, X-ray diffraction and nano-indentation measurements. Weight loss tests were done as per ASTM G 67-04 on the lap joints. Results indicated formation of Al-Fe-Si layer at the weld bead-mild steel interface in both the techniques. The layer was found to be Aluminium rich in MIG –braze sample whereas it was iron rich in the CMT sample. The layer thickness was found to be higher in the toe region than the head region in both samples. The Al-Fe-Si layer preferentially dissolved during the weight loss test of the welds. The thickness of Al-Fe-Si layer for MIG-braze welds was greater resulting in higher intergranular corrosion. [ABSTRACT FROM AUTHOR]

Highlights • The Green-Kubo and Einstein methods were used to predict transport properties. • Equilibrium molecular dynamics is accurate except near-critical conditions. • P - T phase diagram of supercritical fluids is inhomogeneous. • Radial distribution function is used to distinguish the structural transition. Abstract Predicting the transport properties of fuels in high-pressure conditions such as those for supercritical combustion has been a major challenge. In this study, molecular dynamics method of optimised potentials for liquid simulations force field is used to model the diesel fuel surrogate, i.e. n -Dodecane molecule. The Green-Kubo and Einstein methods are used to predict basic transport properties with conditions ranging from the high-pressure nozzle condition (150 MPa, 363 K) to the supercritical chamber environment (6 MPa, 900 K). The computed values agree well with experimental results in conditions with temperature and pressure far away from the critical point. But large discrepancies are observed in the neighborhood of the critical region due to density fluctuation and the critical divergence. The bulk viscosity of n -Dodecane is calculated and found to be hundreds of times greater than shear viscosity in supercritical conditions which cannot be ignored in computational fluid dynamics simulations. The inhomogeneity of supercritical fluids associated with the Widom and Frenkel lines is studied by mapping the loci of the extrema and "ridges" for compressibility coefficient, heat capacity, density fluctuation and velocity autocorrelation function on the P-T phase diagram. In addition, a new criterion is developed to distinguish inhomogeneity and structural transition of n -Dodecane into the "rigid-like", "liquid-like" and "gas-like" fluids, by evaluating the decay of radial distribution function peak heights quantitatively. [ABSTRACT FROM AUTHOR]

Graphical abstract A novel perovskite solar cell was designed based on 3D hierarchical TiO 2 spheres as efficient charge extraction thin film, with a high photo-conversion efficiency due to enhance light scattering, light harvesting, better penetration of the perovskite in the porous HTSs network and facilitated charge extraction and electron transport. Highlights • Three morphologically different TiO 2 substrates were synthesized hydrothermally. • They were applied as ETLs in PSCs, with and without a TiO 2 compact layer. • Fast charge transport, enhanced light absorption and less charge recombination. • The PSCs based on hierarchical TiO 2 spheres, yielded an efficiency of 15.08%. Abstract Recently, organo-metal halide perovskite (e.g., CH 3 NH 3 PbI 3) solar cells have shown a significant surge in progress and efficiency. The photovoltaic performance of perovskite solar cells (PSC) extensively depends on the morphology of the materials at nano-level, because the intrinsic electrical, optical and electrochemical properties also change with a change in morphology. Different TiO 2 nanostructures with diverse dimensionalities, 0D hollow TiO 2 nanoparticles (HTNPs), 3D hollow TiO 2 mesospheres (HTMSs) and 3D hierarchical TiO 2 spheres (HTSs) were synthesized hydrothermally. The PSCs based on 3D HTSs or 3D HTMSs as electron transport layers (ETLs) shows better performance than the PSCs fabricated with 0D HTNPs as ETL. The enhanced results can be attributed to the better penetration of the perovskite materials in the porous network of the HTSs or HTMSs and decreased interfacial recombination due to superior charge extraction and electron transport at the HTSs/CH 3 NH 3 PbI or HTMSs/CH 3 NH 3 Pb interfaces. By using a self-assembled TiO 2 compact layer (c-TiO 2), followed by a mesoporous layer of HTSs, produces PSCs with an excellent efficiency of 15.08%. Such c-TiO 2 -ETL films may improve PSCs performance by enhancing electron extraction and block the photogenerated holes. [ABSTRACT FROM AUTHOR]

Abstract We report on strategies that improve Se-derivative based solar cells performance. With this aim, a compact thin film based on ZnO nanoparticles is deposited onto fluorine doped tin oxide (FTO) as an electron-transport layer, in thermally evaporated Ga x Se 10-x based solar cells. ZnO nanoparticles films are synthesized by sol-gel process whereas Ga x Se 10-x material is obtained by mechanical alloying. Using current-voltage measurements, impedance spectroscopy, and capacitance-voltage profiling, device characteristics and performance limiting factors are revealed and discussed. Particularly, the use of ZnO nanoparticles results in improved device performance as well as long-term stability. In comparison to Se-only devices with the structure FTO/Se/Au (power conversion efficiency of 0.98%), under 100 mW/cm2 AM 1.5 G illumination the devices achieved a power conversion efficiency of 2.7% with the structure FTO/ZnO/GaSe 9 /Au (open circuit voltage of 0.71 V, short-circuit current of 7.9 mA/cm2). Hence, an increase of around 175% in the power conversion efficiency is obtained in comparison to Se-only devices. In addition, the effect of others parameters, like thickness of the active layer as well as the gallium contents in the alloy, are discussed. Highlights • Effects of gallium content in Ga x Se 10-x based solar cells is investigated. • Planar p – n junction solar cells with the structure FTO/ZnO/Ga x Se 10-x /Au provide a PCE of 2.7%. • ZnO nanoparticles enhance both charge collection capability and long-term stability. • Charge generation and recombination processes are identified by impedance spectroscopy. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The anisotropic thermoelectric properties of AgIn 5 Te 8 are identified. • The carrier concentration significantly impacts on the thermoelectric properties. • The lattice thermal conductivity is obtained and agrees to the experimental data. • The maximum ZT of 2.28 is achieved for p -type AgIn 5 Te 8 at 700 K along xx direction. Abstract The synthesis of AgIn 5 Te 8 is realized and the thermoelectric properties dependent on temperature is examined. However, the mechanism remains unclear and the synergistic effect of the temperature and the carrier concentration on thermoelectric properties is not explored. Here, the electronic transport properties are calculated by using the first-principles density functional theory combined with the semi-classical Boltzmann transport theory. The relaxation time is estimated by the deformation potential theory. The lattice thermal conductivity is evaluated by the Slack's model, and the result is in good agreement with the experimental value. High anisotropic behavior is identified for the thermal and electronic transport properties, which supports the experimental observation. By tuning the carrier concentration and temperature, a maximum thermoelectric figure of merit of 2.28 can be achieved for p -type AgIn 5 Te 8 in xx direction. The present results provide insight into the thermoelectric properties of AgIn 5 Te 8 and a guide to prepare thermoelectric materials with AgIn 5 Te 8. [ABSTRACT FROM AUTHOR]

• Symbiotic-structured TiO 2 spheres were obtained with tunable properties. • TiO 2 spheres provided extra transport paths and suppressed carrier recombination. • The symbiotic-structured TiO 2 spheres-based device showed the PCE of 9.58%. Due to the excellent light scattering and dye loading ability, mesoporous TiO 2 microspheres are vastly utilized in dye-sensitized solar cells (DSSCs) to serve as photoanode. Despite of the good electron transport properties due to the unique geometry of mesoporous TiO 2 microspheres, the existence of large holes between adjacent microspheres limits the formation of necking and deteriorates the device performance. In this work, we report a simple 2-step process to synthesize symbiotic structured TiO 2 microspheres treated with different ammonia concentrations. Meanwhile, the nitrogen doping of TiO 2 microspheres is also introduced while ammonia treatment is performed and as a result, the charge transport property is greatly improved. By using the symbiotic structured TiO 2 to substitute pure TiO 2 microspheres photo anode, the photovoltaic performance of DSSCs was greatly improved from 8.77% to 9.58%. It is demonstrated that the improvement is mainly due to the improved charge transportation property of symbiotic structured TiO 2 photoanodes and the effective suppression of carrier recombination. The results give us a comprehensive understanding of electron transport and recombination mechanism in mesoporous TiO 2 microspheres, which will provide significant information for the optimization of TiO 2 structures for DSSC and other optoelectrical applications. [ABSTRACT FROM AUTHOR]

Abstract We report on the structural, magnetic and transport properties of Ru doped Ni 50− x Ru x Mn 38 Sb 12 (x = 0, 3 and 4) alloys. The alloys are found to crystallize in orthorhombic phase for x = 0, orthorhombic plus cubic phase for x = 3 and purely cubic for x = 4 respectively, at room temperature. Extended x-ray absorption fine structure (EXAFS) spectroscopy confirms the orthorhombic and cubic structure for x = 0 and 4 respectively while x = 3 shows mixed austenite and martensite phases, at room temperature. Temperature dependent EXAFS data confirms, first order structural transition from cubic austenite phase to orthorhombic martensite phase occurs at 305 and 265 K for x = 3 and 4 respectively, upon cooling. This is in addition to the second order magnetic phase transition at 350, 330 and 326 K for x = 0, 3 and 4 respectively. The change in the magnetic entropy around the martensitic transition is found to be about 19.5 and 12.3 Jkg − 1 K − 1 for x = 3 and 4, while it is 7.0 Jkg − 1 K − 1 for x = 0. These values (for x = 3 and 4) are large when compared to Ni 50 Mn 38 Sb 12 (7 Jkg − 1 K − 1 ). Exchange bias field is found to be 383, 362 and 240 Oe at 3 K for x = 0, 3 and 4 respectively. Temperature dependent resistivity of the alloys also confirms the first order phase transition. Magnetoresistance is found to be 9.0% for x = 3, 3.5% for x = 4 and 6.0% for x = 0 respectively near martensite transition. Large resistivity difference between martensitic and austenite phases is due to the difference in the carrier concentration by at least one order. Anomalous Hall contribution ρ x y AHE distinguishes martensite and austenite phases. Highlights • Ni 50-x Ru x Mn 38 Sb 12 are investigated using magnetization, resistivity and EXAFS. • EXAFS confirms orthorhombic to cubic phase transition below martensite temperature. • Δ S mag = 19.5 and 12.3 Jkg−1K−1 for x = 3 and 4, respectively. • H EB = 570 & 400 Oe at 3 K while RCP = 83 & 59 Jkg−1 for x = 3 and 4 respectively. • Anomalous Hall contribution distinguishes the martensite and the austenite phases. [ABSTRACT FROM AUTHOR]

Highlights • Hf-In-ZnO (HIZO) as electron transport Layer for inverted organic solar cells (iOSC). • Twice lifetime of encapsulated HIZO-iOSC vs. currently used PFN-iOSC. • Reduced S-shape deformation in the JV curves of HIZO-iOSC vs. PFN-iOSC. Abstract In this study, we report the use of Hafnium-Indium-Zinc-Oxide (HIZO) as electron transport layer (ETL) in inverted organic solar cells (iOSCs) using a bulk heterojunction of Poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PTB7) and [6,6]-phenyl C71 butyric acid methyl ester (PC 70 BM) as active layer. The absorption spectrum and performance parameters obtained are compared to those obtained for similar iOSCs where the ETL was poly [(9,9-bis (30- (N,N-dimethylamino) propyl) -2,7-fluorene) -alt-2,7- (9,9-dioctylfluorene)] (PFN). Initially, devices showed the S-shaped current–voltage curve that has been modeled using a three-diode equivalent circuit model. This phenomenon can be removed by repeating electrical sweep-cycles under illumination. The degradation under nitrogen atmosphere and under encapsulation was also analyzed and compared with the degradation of the iOSCs using PFN. It was observed that the degradation of encapsulated HIZO-iOSC was twice slower than that of PFN-iOSCs. This increase in stability can be attributed to the Hf atoms, which have a stronger thermodynamic tendency to form metal oxides, suppressing the dissociation of HIZO. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • NiO x nanoparticles with different concertation of cobalt ions are synthesized. • Co-NiO x layers are fabricated at low-temperature process as a hole transport layer. • The band alignment is optimized by decreased work function of Co-NiO x layer. • The conductivity of Co-NiO x films is improved to 6.20 × 10 - 6 S c m - 1 . • Conversion efficiency is improved to 14.5% using 1 mol% Co-NiO x. Abstract We have synthesized cobalt-doped NiO x nanoparticles containing 0.5, 1, 2, 5 and 10 mol% cobalt ions and have investigated their electronic properties, which can be processed into smooth and pinhole-free layers at low temperature (<150 °C) as hole transport layers (HTLs) for perovskite solar cells (PSCs). We have revealed that the relationship between conductivity of HTLs and hole extraction properties to improve the photovoltaic performance. The thin film of cobalt-doped NiO x nanoparticles showed higher conductivities compared to pristine NiO x nanoparticles. Consequently, PSCs with power conversion efficiencies over 14.5%, an improvement from 11.5% for those with the pristine NiO x -based HTL, have been obtained. This work will contribute to the development of doped metal oxide HTLs, which are processable at low temperature. [ABSTRACT FROM AUTHOR]

Abstract Measurements of the thermal conductivity of supercritical n-hexane performed in a coaxial cylinder cell operating in steady state conditions are reported. The present 1321 data of the thermal conductivity of n-hexane were carried out along ten quasi-isotherms above the critical temperature. These data cover the temperature range from 508.17 K to 553.00 K and the pressure range 0.l to 10 MPa. An analysis of the various sources of error leads to an estimated uncertainty that do not exceed 4% (95 level of confidence). The parameters of a background equation previously determined from 577 data of the thermal conductivity of gas and liquid n-hexane are reused here in order to analyze the critical enhancement of the thermal conductivity as a function of temperature and density. A set of theoretical Ising-like equations are re-formulated to describe the thermal conductivity critical enhancement along the near-critical isochoric lines in terms of the effective power laws fitting the singular behavior of the needed fluid properties as functions of the finite temperature distance to the critical point. Assuming the knowledge of the regular temperature behavior of the viscosity, the critical enhancement of the thermal conductivity appears then only characterized by a single effective amplitude. Such a separated analysis of the well-defined temperature effects provides the empirical functional form of the density effects, as a 6th-order polynomial density function, which can be normed whatever the temperature. Finally, our complete formulation of the total thermal conductivity describes, within three standard deviations (with SD = 1.0388%), the 1898 thermal conductivity measurements of n-hexane from 293 to 612 K and densities up to 670 kg m−3. Highlights • We presented the first measurements of the thermal conductivity of n-hexane in the supercritical region, along ten isotherms ranging from 508.17 to 553.00 K and at pressures up to 10 MPa with an estimated experimental uncertainty of 3 %. • These measurements represent 1321 new data of the thermal conductivity, which are analyzed to address the development of wide-ranging correlating equations. • The complete correlating equations are able to provide calculated thermal conductivity of n-hexane from 293 to 612 K and densities up to 670 kg.m-3. • The resulting percentage standard deviation is 1.0388% from 1898 experimental thermal conductivity data, including thus 577 data previously measured in the gaseous and liquid n-hexane. [ABSTRACT FROM AUTHOR]

Highlights • We constructed a transverse loading device that can apply a uniform compression perpendicular to superconducting tape. • The critical current and transport AC losses under transverse compression of YBCO CC were investigated. • The behaviors of Ic and /or transport AC losses in Bi2223-Ag during transverse compression were revealed. Abstract We designed a transverse loading device that can apply a more uniform compressive force perpendicular to superconducting tape than previously designed equipment. The effective compressive length and width reached up to 100 and 20 mm, respectively. The critical current (I C) and/or transport AC losses of the superconducting tape during transverse compression could be measured using this equipment. We used YBa 2 Cu 3 O 7−x -coated conductor (YBCO CC) specimens with copper stabilizing layers of different thickness to investigate the characteristics of the critical current and transport AC losses under transverse compression loading. For comparison, several Bi-2223/Ag samples were also tested. A critical stress was observed for the compression process (the same as that for axial tension), and beyond this stress, I C degraded irreversibly. For the transport AC losses behavior of the YBCO CC and Bi-2223/Ag specimens, below the critical stress value, the AC losses remained almost unchanged with the increase of the compressive stress at the same current; while above the critical stress value, at increasing compressive stress, the AC losses increased rapidly and the normalized AC losses for normalized current decreased. [ABSTRACT FROM AUTHOR]

Highlights • (Mg,Fe)O rheology at CMB conditions is studied through 2.5D dislocation dynamics. • Fe-rich (Mg,Fe)O viscosity is 10 orders of magnitude below that of Mg-rich (Mg,Fe)O. • The influence of weak Fe-rich (Mg,Fe)O on the dynamics of ULVZs is explored. Abstract The viscosity of the lower mantle results from the rheological behavior of its two main constituent minerals, aluminous (Mg,Fe)SiO 3 bridgmanite and (Mg,Fe)O ferropericlase. Understanding the transport properties of lower mantle aggregates is of primary importance in geophysics and it is a challenging task, due to the extreme time-varying conditions to which such aggregates are subjected. In particular, viscosity is a crucial transport property that can vary over several orders of magnitude. It thus has a first-order control on the structure and dynamics of the mantle. Here we focus on the creep behavior of (Mg,Fe)O at the bottom of the lower mantle, where the presence of thermo-chemical anomalies such as ultralow-velocity zones (ULVZ) may significantly alter the viscosity contrast characterizing this region. Two different iron concentrations of (Mg 1–x Fe x)O are considered: one mirroring the average composition of ferropericlase throughout most of the lower mantle (x = 0.20) and another representing a candidate magnesiowüstite component of ULVZs near the base of the mantle (x = 0.84). The investigated pressure-temperature conditions span from 120 GPa and 2800 K, corresponding to the average geotherm at this depth, to core-mantle boundary conditions of 135 GPa and 3800 K. In this study, dislocation creep of (Mg,Fe)O is investigated by dislocation dynamics (DD) simulations, a modeling tool which considers the collective motion and interactions of dislocations. To model their behavior, a 2.5 dimensional dislocation dynamics approach is employed. Within this method, both glide and climb mechanisms can be taken into account, and the interplay of these features results in a steady-state condition. This allows the retrieval of the creep strain rates at different temperatures, pressures, applied stresses and iron concentrations across the (Mg,Fe)O solid solution, providing information on the viscosity for these materials. A particularly low viscosity is obtained for magnesiowüstite with respect to ferropericlase, the difference being around 10 orders of magnitude. Thus, the final section of this work is devoted to the assessment of the dynamic implications of such a weak phase within ULVZs, in terms of the viscosity contrast with respect to the surrounding lowermost mantle. [ABSTRACT FROM AUTHOR]

Abstract We have studied transport properties, as well as the self-diffusion, viscosity and thermal conductivity of fluids by using new semi-theoretical model based on the rough hard-sphere (RHS) theory. In the present study, the proposed RHS is employed to model the transport properties of CH 4 , CCl 4 , C 6 H 6 , CHCl 3 , H 2 O , R134a , 2 - EHB , PE and PS for temperatures ranging from 110 to 530 K and at pressures up to 1000 MPa. Parameters appeared in the new RHS model are taken from previously developed perturbed hard-trimer chain (PHTC) equation of state. From 174 experimental data points examined, the average absolute relative deviation AARD of predicted viscosities for CH 4 , H 2 O and R134a was found to be 6.59%. In the case of self-diffusion, the new RHS -based model correlated and predicted 139 experimental data points with AARD equal to 4.06%. The proposed RHS -based model has also been extended to predicted 228 experimental data points of thermal conductivity for CH 4 , H 2 O and R134a with AARD equal to 4.54%. In addition, molecular dynamics (MD) calculations were performed with the GROMACS simulation package and to investigate the thermophysical properties of fluids. The MD approach enabled us to calculate the density, viscosity, self-diffusion and thermal conductivity of CH 4 and C 6 H 6. The computed value of these properties agreement with experimental values. Finally, MD is applied to calculate density of binary water–alcohol mixtures including water–methanol and water–ethanol. Highlights • The transport properties is calculated by combination of PHTC EOS and RHS theory. • The new RHS is proposed to model the self-diffusion of fluids. • The agreement between the calculated and the literature data is acceptable. • The small value of AARD confirm the ability of RHS theory. • MD calculations were performed to investigate the thermophysical properties of fluids. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Low cost method to obtain MgFe 2 O 4 thin films by DC magnetron sputtering. • Obtaining high magnetization and rectangular hysteresis loops ferrite thin films. • Relation between magnetic characteristics and microstructure was established. • High photoconductivity detected in films growth on STO substrate. • Photo-carriers mechanism was associated to films/substrate interface. Abstract In order to study the substrate influence in Mg ferrite properties, thin films were simultaneously grown by DC magnetron sputtering on different substrates (MgO (1 0 0) and SrTiO 3 (1 0 0)). In both cases samples show high values of saturation magnetization and Curie temperatures above room temperature. While in the case of the sample grown on MgO the hysteresis loops indicate the existence of more than one ferrimagnetic component and lower value of remanence to saturation ratio, the deposited one on SrTiO 3 is mono-component and has a rectangular-shape magnetic loop at all temperatures below 300 K. The difference is attributed to different microstructures due to the misfit strain caused by the different lattice constants between substrates and ferrite. The electric transport and photoconductivity properties have been investigated on both samples. Thin film growth on STO presents an increase around 40% of the photoconductance in the near UV range. The photocurrent shows two clear onsets that coincide with the indirect and direct band gaps of STO indicating the important role of this substrate in the generation of photo carriers. [ABSTRACT FROM AUTHOR]

Abstract Films of Sb-doped SnO 2 were deposited by dip-coating technique. The morphology analysis showed that the microstructure of the samples exhibits many shaped nano-sized crystallites homogenously dispersed on the surfaces. The roughness varies with Sb-content, implying that doping has an important effect on the surface morphology of the films. Raman and FTIR-ATR investigations revealed that the films exhibit a vibration mode at 564 cm−1 ascribed to the amorphous phase overlapping the crystallites. Thus, the selection rule (k = 0) is relaxed because of disorder and reduced crystallites size to nanoscale by Sb-doping, which may explain the broadening and shift of the lattice modes. The vibration of sub-bridging oxygen atoms seems to be significantly affected by oxygen vacancies and Sb-derived surface mode has been identified at 578 cm−1. The optical band gap is red-shift due to the introduction of localized states in the SnO 2 bulk associated to Sb-doping and oxygen defects. The refractive index varies due the enhanced grain boundaries effect and surface disorder induced by Sb incorporation in the crystal lattice. The photoconductivity (σ ac) shows a dispersion pattern with two regions, corresponding to extrinsic and intrinsic conductivities. Under UV-illumination, the electrical charge transport mechanism changes from multi-hopping to single-hopping at higher temperatures. [ABSTRACT FROM AUTHOR]

Although the content of Eu in the single crystal (La0.8Eu0.2)4/3Sr5/3Mn2O7 is very small, the effects of Eu ions on the magnetic and transport properties are quite evident at low temperature due to the large size difference between Eu and La ions, compared with the crystal's parent compound La5/3Sr4/3Mn2O7. The sharp jumps in M(H) and ρ (H) curves suggest that a first-order Field-induced transition from magnetically disorder state to 3D long-range ferromagnetic metallic state takes place at 2 K. Both resistivity and magnetization dependents on the magnetic history and clearly demonstrate hysteretic behaviors. These results indicate that the system has a very fragile ground state and the local lattice distortions in bilayer manganites play an important role in the physical properties. [ABSTRACT FROM AUTHOR]

Transport properties of Indium Arsenide (InAs) films deposited at different working pressures are investigated in the temperature interval of T ∼ 2-250 K. Electrical transport of InAs films is related to the degree of disorder, which increases as working pressure increases. Activated conductivity models satisfactorily describe conduction in the localized band-tails at high temperatures, while conductivity shows metallic characteristic at low temperatures for μc-InAs samples. The critical conductivity exponent of μc-InAs is close to 1, which indicates that μc-InAs samples exhibit a close proximity to the metal-insulator transition. The product of aB and n1/3 for samples S1 and S2 is 0.236 and 0.207, respectively, which is roughly consistent with the Mott criterion. But for α-InAs samples in the high temperature region, electron transport is described by conduction in extended states and in localized states near the Fermi level. Furthermore, a crossover from Mott variable range hopping (VRH) to the Efros-Shklovskii VRH mechanism is observed in α-InAs thin films at low temperatures. [ABSTRACT FROM AUTHOR]

We fused zigzag graphene to boron nitride nanoribbons by gradually doping C atoms at only one edge of the ribbons to design a hybridized ZBxNyCz (x + y + z = 12) structure. To create asymmetric edge hydrogenation, the ZBxNyCz ribbons were monohydrogenated (N-H) at one edge and dihydrogenated (C-H2) at the opposite edge, and the structure was subsequently labeled as H-ZBxNyCz-H2. On the basis of density functional theory and non-equilibrium Green's function, our simulation revealed that H-ZBxNyCz-H2-based devices present a variety of abnormal spin-polarized transport properties. When the value of x and y in the H-ZBxNyCz-H2 structure is not equal (i.e., z is an odd number), the spin-polarized currents are restricted, regardless of their ferromagnetic (FM) or anti-ferromagnetic (AFM) state. When x is equal to y (i.e., z is an even number), the H-ZBxNyCz-H2 structure exhibits negative differential resistance and spin-filtering features in the FM state. Conversely, in the AFM state, the spin-polarized currents of the structure exhibit an exceptional oscillation effect with spin polarization as high as 100% at certain bias voltages. By adjusting the width of graphene and the spin states, the resulting hybridized H-ZBxNyCz-H2 structure can be potentially applied to the fabrication of spin nanodevices with exotic functionalities. [ABSTRACT FROM AUTHOR]