论文标题
第一原则II型Weyl Phonons的证据岩石锡硫化盐（SNS，SNSE和SNTE）材料
First-principles evidence of type-II Weyl phonons in rock-salt Tin Chalcogenides (SnS, SnSe & SnTe) materials
论文作者
论文摘要
关于凝结物理学中不同拓扑材料的最新研究通过执行各种理论计算和实验观察，为玻体粒子（如声子）提供了拓扑性质的证据。在这里，使用$ ab $ - $ $ initio $方法研究了SNS，SNSE和SNTE材料的声子的拓扑行为。对于所有这些材料，观察到倾斜的线性带触摸以及沿X-W方向上的带反转的存在。沿X-W方向的声子分散曲线中的拓扑点分别为$ \ sim $ 2.83，$ \ sim $ 2.46和$ \ sim $ 2.51 THz，SNS，SNSE和SNTE分别为THZ。对于SNS，SNSE和SNTE，计算出的Weyl点（WPS）的计算数量分别为56、24和54。这些WPS显示了所有相应材料的保守手性电荷。计算这些化合物的表面局部密度，在这些化合物中清楚地看到了表面弧。如果是SNS，则在2.0-2.2 THz能量区域发现表面弧。同样，研究了同频表面状态，以观察SNX的费米弧的存在（X = S，SE，TE）。当前的第一原理计算预测，SNS，SNSE和SNTE显示II型Weyl语音行为以及拓扑语音表面状态的证据。
Recent studies on different topological materials in condensed matter physics have provided the evidence of topological nature for bosonic particle like phonons by performing various theoretical calculations and experimental observations. Here, the topological behaviours of phonons of SnS, SnSe and SnTe materials in rock-salt structure are investigated using $ab$-$initio$ methodology. For all these materials, the tilted linear band touching is observed along with the presence of band inversion in direction X-W. The topological point in phonon dispersion curve along X-W direction is found to be $\sim$2.83, $\sim$2.46 and $\sim$2.51 THz for SnS, SnSe and SnTe, respectively. The calculated numbers of Weyl points (WPs) is estimated to be 56, 24 and 54 for SnS, SnSe and SnTe, respectively. These WPs have shown conserved Chiral charges for all corresponding materials. The surface local density of states is computed for these compounds, where the surface arc is clearly seen. In case of SnS, the surface arc is found at 2.0 - 2.2 THz energy region. Also, the isofrequency surface states are investigated to observe the presence of Fermi arc for SnX (X = S, Se, Te). The present first-principles calculation predicts that SnS, SnSe and SnTe show type-II Weyl phononic behaviour along with evidence of topological phononic surface states.
