论文标题
ta $ _2 $ m $ _3 $ te $ _5 $（m = pd，ni）
Quantum Spin Hall Effect in Ta$_2$M$_3$Te$_5$ (M = Pd, Ni)
论文作者
论文摘要
量子自旋大厅（QSH）效应对旋转和量子计算的潜在应用有很大的希望引起了理论和实验研究人员的广泛研究兴趣。在这里，我们预测单层TA $ _2 $ PD $ _3 $ te $ _5 $可以是基于第一原理计算的QSH绝缘子。层中的夹具绑定能量中的van der waals ta $ _2 $ pd $ _3 $ _3 $ _5 $是19.6 mev/a $^2 $;因此，可以通过去角质很容易获得其单层/薄膜结构。 Fermi级别（$ e_f $）附近的频段反转是一个内在特征，它发生在Ta-5d $和PD- $ 4D $轨道之间，而无需自旋轨道耦合（SOC）。 SOC效应打开了全球差距，并使系统成为QSH绝缘体。凭借$ d $ - $ d $带反向的功能，单层TA $ _2 $ _2 $ _3 $ _3 $ _3 $ _5 $的非平凡拓扑的特征是时间逆转拓扑不变性$ \ mathbb z_2 = 1 $，它由一位数（1D）Wilson loop方法计算为我们的第一个actiples in Cond-princ in In In Im Incip incip incip incip concip concluct。还使用表面绿色的功能方法获得了螺旋边缘模式。我们的计算表明，ta $ _2m_3 $ te $ _5 $（$ m = $ pd，ni）中的QSH状态可以通过外部应变来调节。这些单层和薄膜为实现QSH效果以及相关设备提供了可行的平台。
Quantum spin Hall (QSH) effect with great promise for the potential application in spintronics and quantum computing has attracted extensive research interest from both theoretical and experimental researchers. Here, we predict monolayer Ta$_2$Pd$_3$Te$_5$ can be a QSH insulator based on first-principles calculations. The interlayer binding energy in the layered van der Waals compound Ta$_2$Pd$_3$Te$_5$ is 19.6 meV/A$^2$; thus, its monolayer/thin-film structures could be readily obtained by exfoliation. The band inversion near the Fermi level ($E_F$) is an intrinsic characteristic, which happens between Ta-$5d$ and Pd-$4d$ orbitals without spin-orbit coupling (SOC). The SOC effect opens a global gap and makes the system a QSH insulator. With the $d$-$d$ band-inverted feature, the nontrivial topology in monolayer Ta$_2$Pd$_3$Te$_5$ is characterized by the time-reversal topological invariant $\mathbb Z_2=1$, which is computed by the one-dimensional (1D) Wilson loop method as implemented in our first-principles calculations. The helical edge modes are also obtained using surface Green's function method. Our calculations show that the QSH state in Ta$_2M_3$Te$_5$ ($M=$ Pd, Ni) can be tuned by external strain. These monolayers and thin films provide feasible platforms for realizing QSH effect as well as related devices.
