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排序方式: 共有193条查询结果,搜索用时 31 毫秒
51.
The solid solution series Li2Ir1-xRhxO3 is synthesized for several values of x between 0 and 1. The compounds possess a monoclinic layered structure (space group C2/m) throughout the solid solution range with the lattice constants following Vegard's relationship. Magnetization and resistivity data below room temperature are presented. The effective magnetic moment (μeff) is reduced below the value obtained by interpolating between the end-members, presumably due to nearest neighbor charge exchange leading to non-magnetic Ir5+/Rh3+ pairs. Surprisingly, the degree of reduction of μeff cannot be explained by a random mixture of Ir and Rh and, in particular, is strongly asymmetric around x = 0.5. This anomalous moment reduction possibly results from the difference in on-site Coulomb repulsion between Ir and Rh ions. 相似文献
52.
We discuss and determine the conditions under which a Kondo-insulator phase is stable. We show for CeRhSb that the dependence of the onsite hybridization energy Vdf between the Ce 5d and Ce 4f states on the number of valence electrons or the unit cell volume is decisive for the hybridization Kondo gap formation. We also propose the method for determining the energy Vdf from the ab initio calculations. This approach supplies an accurate Kondo-insulator-metal transition in agreement with the recent experimental data. 相似文献
53.
54.
We consider the differential conductance of a periodically driven system connected to infinite electrodes. We focus on the situation where the dissipation occurs predominantly in these electrodes. Using analytical arguments and a detailed numerical study we relate the differential conductances of such a system in two and three terminal geometries to the spectrum of quasi-energies of the Floquet operator. Moreover these differential conductances are found to provide an accurate probe of the existence of gaps in this quasi-energy spectrum, being quantized when topological edge states occur within these gaps. Our analysis opens the perspective to describe the intermediate time dynamics of driven mesoscopic conductors as topological Floquet filters. 相似文献
55.
《Physics letters. A》2014,378(26-27):1893-1896
We propose an entanglement detector composed of two quantum spin Hall insulators and a side gate deposited on one of the edge channels. For an ac gate voltage, the differential noise contributed from the entangled electron pairs exhibits the nontrivial step structures, from which the spin entanglement concurrence can be easily obtained. The possible spin dephasing effects in the quantum spin Hall insulators are also included. 相似文献
56.
We develop a microscopic theory of the weak localization of two-dimensional massless Dirac fermions, which is valid in the whole range of classically weak magnetic fields. The theory is applied to calculate the magnetoresistance caused by the weak localization in graphene and topological insulators. 相似文献
57.
Manisha Samanta Koushik Pal Umesh V. Waghmare Kanishka Biswas 《Angewandte Chemie (International ed. in English)》2020,59(12):4822-4829
A challenge in thermoelectrics is to achieve intrinsically low thermal conductivity in crystalline solids while maintaining a high carrier mobility (μ). Topological quantum materials, such as the topological insulator (TI) or topological crystalline insulator (TCI) can exhibit high μ. Weak topological insulators (WTI) are of interest because of their layered hetero‐structural nature which has a low lattice thermal conductivity (κlat). BiTe, a unique member of the (Bi2)m(Bi2Te3)n homologous series (m:n=1:2), has both the quantum states, TCI and WTI, which is distinct from the conventional strong TI, Bi2Te3 (where m:n=0:1). Herein, we report intrinsically low κlat of 0.47–0.8 W m?1 K?1 in the 300–650 K range in BiTe resulting from low energy optical phonon branches which originate primarily from the localized vibrations of Bi bilayer. It has high μ≈516 cm2 V?1 s?1 and 707 cm2 V?1 s?1 along parallel and perpendicular to the spark plasma sintering (SPS) directions, respectively, at room temperature. 相似文献
58.
Summary An attempt is made to present a simplified analysis of the thermoelectric power in II–VI semiconductors in the presence of
quantization of band states under different physical conditions. The thermopower decreases with increasing electron concentration
in different manners, which is a direct consequence of band state quantization. We have plotted the thermopower with various
other physical variables and the same power exhibits different types of oscillations in low-dimensions, respectively. The
well-known results for parabolic energy bands have also been obtained as special cases of our generalized formulations under
certain limiting conditions. In addition, the theoretical results are in quantitative agreement with the experimental data. 相似文献
59.
采用外耦合电容式射频辉光放电等离子体 CVD 系统,在低于300℃的衬底温度下,制备出了 a—Si(1-x)C_x∶H 钝化膜.对含碳量不同的3种样品作了热稳定性实验(即高温存放、温度循环和退火).另外,还对同一号样品做了在不同温度下退火30min 的实验.结果表明,此钝化膜的释氢温度高于600℃.具有很好的热稳定性. 相似文献
60.
Using derivative expansion applied to the Wigner transform of the two- point Green function we analyse the anomalous quantum Hall effect (AQHE), and the chiral magnetic effect (CME). The corresponding currents are proportional to the momentum space topological invariants. We reproduce the conventional expression for the Hall conductivity in 2+1 D. In 3+1 D our analysis allows to explain systematically the AQHE in topological insulators and Weyl semimetals. At the same time using this method it may be proved, that the equilibrium CME is absent in the wide class of solids, as well as in the properly regularized relativistic quantum field theory. 相似文献