BaHgSn：一种具有表面沙漏费米子的Dirac半金属
BaHgSn: A Dirac semimetal with surface hourglass fermions
摘要：
我们提出BaHgSn是一种狄拉克半金属（DSM），它可以在非对称滑移对称性的保护下拥有沙漏状表面态（HSSs）。与具有相同HSSs的同构拓扑晶体绝缘体KHgSb相比，BaHgSn在$Γ$点处具有额外的带反转。这种能带反转是由于Hg-Sn蜂窝层之间的层间耦合比Hg-Sb蜂窝层之间的层间耦合强，导致BaHgSn中沿层堆叠方向$Γ$ - $A$出现体狄拉克节点。另外，由镜面$\overline{M}_{z}$保护的镜面陈数$C_{i}$（$k_z$ =0）从KHgSb中的2变为BaHgSn中的3。因此，当沿$y$轴施加压缩单轴应变以破坏保护DSM状态的旋转对称性时，BaHgSn变成具有$(1;000)$的$Z_{2}$指数的强拓扑绝缘体，并且拓扑表面狄拉克锥与（010）表面上的HSS共存。威尔逊环谱已被计算，以验证这些拓扑特征。计算的表面态，费米面和准粒子干涉图案准备与实验测量进行比较。
英文摘要：
We proposed that BaHgSn is a Dirac semimetal (DSM) which can host hourglass-like surface states (HSSs) as protected by nonsymmorphic glide symmetry. Compared to KHgSb, an isostructural topological crystalline insulator with the same HSSs, BaHgSn has an additional band inversion at $Γ$ point. This band inversion is induced by the stronger interlayer coupling among Hg-Sn honeycomb layers than that among Hg-Sb-layers in KHgSb, which leads to bulk Dirac nodes in BaHgSn along the layer stacking direction $Γ$-$A$. In addition, the mirror Chern number $C_{i}$ protected by the mirror plane $\overline{M}_{z}$ ($k_z$=0) changes from 2 in KHgSb to 3 in BaHgSn. Therefore, when a compressive uniaxial strain is applied along the $y$ axis to break the rotation symmetry protecting the DSM state, BaHgSn becomes a strong topological insulator with $Z_{2}$ indices of $(1;000)$ and the topological surface Dirac cone co-exists with HSSs on the (010) surface. The Wilson-loop spectra have been calculated to verify these topological features. The calculated surface states, the Fermi surfaces and their quasiparticle interference patterns are ready to be compared with experimental measurements.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
