标题： 莫尔能带理论用于M谷扭曲的过渡金属二硫化物 显示英文标题

标题： Moiré band theory for M-valley twisted transition metal dichalcogenides

摘要： 我们研究了IV族和IVB族三元过渡金属二硫属化物（TMDs）MX$_{2}$（M$=$Ti、Zr、Hf、Sn和X$=$S、 Se、Te）的扭曲双层作为莫尔材料平台的可行性。 我们表明，这些系统中的低能导带态可以通过一组三个涌现的周期性哈密顿量准确描述，我们从一个小单元密度泛函理论计算中为一个代表性同质双层推导出这些哈密顿量，使用局部位移近似。 在单层形式下，这些TMDs的导带极小值在三个非等价的布里渊区$M$点附近具有各向异性的有效质量，这意味着当考虑自旋时，莫尔带模型有六种风味。 由于每个$M$点是时间反演不变的，因此在输运中通过各向异性而不是通过石墨烯和$K$-谷TMD基莫尔多层中常见的反常霍尔和磁圆二色效应来表明自发谷极化。 显示英文摘要

摘要： We examine the viability of twisted bilayers of group IV and IVB trigonal transition metal dichalcogenides (TMDs) MX$_{2}$ (M$=$Ti, Zr, Hf, Sn and X$=$S, Se, Te) as a moir\'{e} material platform. We show that the low energy conduction band states in these systems are accurately described by a set of three emergent periodic Hamiltonians which we derive for a representative homobilayer from small unit cell density functional theory calculations using a local displacement approximation. In monolayer form, these TMDs have conduction band minima with anisotropic effective masses near the three inequivalent Brillouin zone $M$ points, implying a moir\'e band model that has six flavors when spin is included. Because each $M$ point is time-reversal invariant, spontaneous valley polarization is signaled in transport by anisotropy instead of by the anomalous Hall and magnetic circular dichroism effects commonly seen in graphene and $K$-valley TMD based moir\'{e} multilayers.