Narimani Mitra, Yalameha Shahram, Nourbakhsh Zahra
J Phys Condens Matter. 2020 Jun 10;32(25):255501. doi: 10.1088/1361-648X/ab6046.
Topological insulators with novel surfaces or edge states are the topological nature sequel of bulk electronic wave functions of these materials. The observed signatures in the electronic structure of topological insulators can make them excellent candidates for thermoelectric materials. Low dimensional materials such as phosphorene and BiTe nanowire have been confirmed to be desirable for the design of devices with high thermoelectric performance. So in this work, the phonon modes, formation energy and cohesive energy of LaX (X = Sb, Bi) monolayers are first calculated and investigated. Then the band order of these monolayers is investigated by the band structure calculations and the topological phase of these monolayers is proved by using the calculation of Z topological invariant. The energy band gap and the band inversion strength of these monolayers are evaluated under in-plane strains. Also, the effect of different temperatures and in-plane strains on the thermoelectric performance of LaX monolayers is studied. The results show the high thermoelectric efficiency and d-p topological band inversion of these monolayers under compressive strains.
具有新颖表面或边缘态的拓扑绝缘体是这些材料体电子波函数的拓扑性质延续。在拓扑绝缘体电子结构中观察到的特征使其成为热电材料的优秀候选者。诸如磷烯和BiTe纳米线等低维材料已被证实对于设计具有高热电性能的器件是理想的。因此，在这项工作中，首先计算并研究了LaX（X = Sb，Bi）单层的声子模式、形成能和内聚能。然后通过能带结构计算研究这些单层的能带顺序，并使用Z拓扑不变量的计算证明这些单层的拓扑相。在面内应变下评估这些单层的能带隙和能带反转强度。此外，研究了不同温度和面内应变对LaX单层热电性能的影响。结果表明，在压缩应变下这些单层具有高热电效率和d-p拓扑能带反转。
