Wu Jia-Fang, Ke Sha-Sha, Guo Yong, Zhang Huai-Wu, Lü Hai-Feng
School of Physics and State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China.
Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China.
Phys Chem Chem Phys. 2021 Oct 20;23(40):23196-23202. doi: 10.1039/d1cp02793j.
Ideal topological materials are those stable materials with less nontrivial band crossing near the Fermi surface and a long Fermi arc. By means of first-principles calculations, here we present that the 3D monochalcogenide molybdenum telluride (-MoTe) without an inversion center shows a type-II Weyl semimetal (WSM) phase which cannot checked by symmetry index method. A total of eight Weyl points (WPs) are found in different quadrants of the Brillouin zone (BZ) of -MoTe, which guarantee a long Fermi arc. The WSM phase is robust against the spin-orbit coupling (SOC) effect because of mirror symmetry and time reversal symmetry. It is also found that a topological phase transition can be tuned by strain. For different types of strain, the number of WPs can be effectively modulated to a minimum number, and their energies could be closer to Fermi level. These findings propose a promising material candidate that partly satisfies the ideal WSM criteria and extends the potential applications of the tunable topological phase.
理想的拓扑材料是那些在费米面附近具有较少非平凡能带交叉且费米弧较长的稳定材料。通过第一性原理计算，我们在此表明，无反演中心的三维单硫属化物碲化钼（-MoTe）呈现出一种II型外尔半金属（WSM）相，该相无法通过对称性指标方法来检验。在-MoTe的布里渊区（BZ）的不同象限中共发现了八个外尔点（WPs），这保证了长费米弧。由于镜面对称性和时间反演对称性，WSM相对自旋轨道耦合（SOC）效应具有鲁棒性。还发现拓扑相变可以通过应变来调节。对于不同类型的应变，WPs的数量可以有效地调制到最小数量，并且它们的能量可以更接近费米能级。这些发现提出了一种有前景的材料候选物，其部分满足理想WSM标准，并扩展了可调拓扑相的潜在应用。
