Topological semimetal phases manifested in transition metal dichalcogenides intercalated with 3d metals
Topological semimetal phases manifested in transition metal dichalcogenides intercalated with 3d metals
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DOI：
10.1103/physrevb.100.121112
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发表时间：
2019-04
影响因子：
3.7
通讯作者：
T. Inoshita;M. Hirayama;N. Hamada;H. Hosono;S. Murakami
中科院分区：
文献类型：
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作者：
T. Inoshita;M. Hirayama;N. Hamada;H. Hosono;S. Murakami
为了寻找具有干净带轮廓的稳定拓扑半金属，我们通过执行基于混合功能的从头计算筛选了所有的$3d$金属插入过渡金属二硫族化合物（3dI-TMDCs）。在${k}_{z}=0$平面（无自旋-轨道相互作用）上确定了两类具有12个Weyl点（WPs）的拓扑材料：(a)铁磁Weyl半金属$\ mathm {V}{T}_{3}{X}_{6}$和(b)无自旋Weyl半金属$\ mathm {Mn}{T}_{3}{X}_{6}$（非磁性），其中$T=\text{Nb}$， Ta和$X=\text{S}$, Se。${\mathrm{VNb}}_{3}{\mathrm{S}}_{6}$是(a)类的原型，是半金属的，只有两个带在费米能级相交形成WPs。如果考虑自旋轨道相互作用，则${\ mathm {VNb}}_{3}{\ mathm {S}}_{6}$是基面上磁化强度$\mathbf{m}$只有两个WPs的Weyl半金属，而$\mathbf{m}$是垂直于基面上的铁磁拓扑绝缘体。${\mathrm{MnNb}}_{3}{\mathrm{S}}_{6}$的非磁相本质上是${\mathrm{VNb}}_{3}{\mathrm{S}}_{6}$的无自旋版本，具有同样干净的带型。有趣的是，两种材料都表现出一条连接WPs的准节点线，我们用准镜像对称性和带的轨道性质来解释这一点。3dI-TMDCs是一种化学和热稳定的化学计量化合物，不含有毒元素，是拓扑凝聚态物理研究的可行平台。
In the search for stable topological semimetals with clean band profiles, we have screened all the $3d$ metal-intercalated transition metal dichalcogenides (3dI-TMDCs) by performing hybrid-functional-based ab initio calculations. Two classes of topological materials featuring 12 Weyl points (WPs) in the ${k}_{z}=0$ plane (without spin-orbit interactions) are identified: (a) ferromagnetic Weyl semimetals $\mathrm{V}{T}_{3}{X}_{6}$ and (b) spinless Weyl semimetals $\mathrm{Mn}{T}_{3}{X}_{6}$ (nonmagnetic), where $T=\text{Nb}$, Ta and $X=\text{S}$, Se. ${\mathrm{VNb}}_{3}{\mathrm{S}}_{6}$, prototypical of class (a), is half metallic with only two bands crossing at the Fermi level to form WPs. If spin-orbit interactions are included, ${\mathrm{VNb}}_{3}{\mathrm{S}}_{6}$ is a Weyl semimetal with only two WPs for magnetization $\mathbf{m}$ in the basal plane, whereas it is a ferromagnetic topological insulator for $\mathbf{m}$ normal to the plane. ${\mathrm{MnNb}}_{3}{\mathrm{S}}_{6}$ in the nonmagnetic phase is essentially a spinless version of ${\mathrm{VNb}}_{3}{\mathrm{S}}_{6}$ featuring an equally clean band profile. Interestingly, both materials exhibit a quasinodal line connecting the WPs, which we explain in terms of the quasimirror symmetry and the orbital nature of the bands. 3dI-TMDCs are chemically and thermally stable stoichiometric compounds containing no toxic elements and are a viable platform for the study of topological condensed-matter physics.