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Theoretical study of thermoelectric properties of MoS2Theoretical study of thermoelectric properties of MoS2Theoretical study of thermoelectric properties of MoS2 下载免费PDF全文
We systematically studied the thermoelectric properties of MoS2 with doping based on the Boltzmann transport theory and first-principles calculations. We obtained an optimal doping region (around 1019 cm-3) for thermoelectric properties along in-plane and cross-plane directions. MoS2 in the optimal doping region has a vanishingly small anisotropy of ther- mopower possibly due to the decoupling of in-plane and cross-plane conduction channels, but big anisotropies of electrical conductivity cr and electronic thermal conductivity ke arising from the anisotropic electronic scattering time. The ~ is comparable to the lattice counterpart k1 in the plane, while tq dominates over tee across the plane, The figure of merit ZT can reach 0.1 at around 700 K with in-plane direction preferred by doping. 相似文献
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简要地介绍在纳米复合稀土永磁薄膜材料、各向异性稀土永磁薄膜材料方面的进展.在纳米复合稀土永磁薄膜材料中实现磁性交换耦合和剩磁增强效应,系统地研究了其结构与磁性的关系.制备成功高磁能积的各向异性稀土永磁薄膜材料,比较了Ti 或Mo 缓冲层对Nd-Fe-B薄膜的表面形貌、磁畴结构和磁性能的影响.发现薄膜的表面形貌强烈地依赖于缓冲层的厚度.由于它极大地影响薄膜的成分,溅射速率被证明是控制薄膜的显微结构、表面形貌和磁性能的一个重要因素.在微磁学模型的基础上,通过分析从5到300 K的矫顽力温度依赖关系.研究了各向异性Pr-Fe-B薄膜的矫顽力机制.在晶粒表面,由于磁各向异性的降低和局域退磁场的提高导致的反转畴的形核被确定为控制各向异性Pr-Fe-B薄膜的磁化反转过程的首要机制. 相似文献
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磁场作用下向列型液晶中的分子取向短程关联 总被引:3,自引:0,他引:3
从分子统计理论的观点研究磁场对向列型液晶的作用。将向列型液晶的格胞理论推广到包含磁场作用的情况。这一理论考虑了分子取向短程关联。向列相序参数对约化温度的依赖关系和每个分子的约化内能对约化温度的依赖关系,与计算机模拟结果符合得相当好。计算了各向同性相最低过冷温度,理论结果与实验值和分子场理论的结果进行了比较。 相似文献
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A TWO PARTICLE CLUSTER THEORY FOR UNIAXIAL NEMATIC LIQUID CRYSTALS FORMED BY BIAXIAL MOLECULES 总被引:2,自引:0,他引:2 下载免费PDF全文
A two-particle cluster theory is presented to study uniaxial nematic liquid crystals formed by biaxial molecules, which interact with each other via dispersion forces. The equation for the molecular orientational distribution functions in two-particle cluster approximation is obtained and is solved by an terativemethod. The temperature dependences of the order parameter and of the internal energy per particle are calculated, and the values of the relevant quantities at the nematic isotropic phase transition are given. The present theory, by taking into account the short range correlations between molecules , yields improved results compared with the mean field theory. 相似文献
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The magnon energy band in a four-layer ferromagnetic superlattice is studied by using the linear spin-wave approach and Green's function technique. It is found that three modulated energy gaps exist in the magnon energy band along Kx direction perpendicular to the superlattice plane. The spin quantum numbers and the interlayer exchange couplings all affect the three energy gaps. The magnon energy gaps of the four-layer ferromagnetic superlattice are different from those of the three-layer one. For the four-layer ferromagnetic superlattice, the disappearance of the magnon energy gaps △ω12, △ω23 and △ω34 all correlates with the symmetry of this system. The zero energy gap △ω23 correlates with the symmetry of interlayer exchange couplings, while the vanishing of the magnon energy gaps △ω12 and △ω34 corresponds to a translational symmetry of x-direction in the lattice. When the parameters of the system deviate from these symmetries, the three energy gaps will increase. 相似文献