Shao Dexi, Deng Junze, Sheng Haohao, Zhang Ruihan, Weng Hongming, Fang Zhong, Chen Xing-Qiu, Sun Yan, Wang Zhijun
Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Department of Physics, Hangzhou Normal University, Hangzhou 311121, China.
Research (Wash D C). 2023;6:0042. doi: 10.34133/research.0042. Epub 2023 Feb 24.
Two-dimensional (2D) materials have gained lots of attention due to the potential applications. In this work, we propose that based on first-principles calculations, the (2 × 2) patterned PtTe monolayer with kagome lattice formed by the well-ordered Te vacancy (PtTe) hosts large and tunable spin Hall conductivity (SHC) and excellent hydrogen evolution reaction (HER) activity. The unconventional nature relies on the 1 @ 1 band representation of the highest valence band without spin-orbit coupling (SOC). The large SHC comes from the Rashba SOC in the noncentrosymmetric structure induced by the Te vacancy. Even though it has a metallic SOC band structure, the ℤ invariant is well defined because of the existence of the direct bandgap and is computed to be nontrivial. The calculated SHC is as large as 1.25 × 10 (Ω cm) at the Fermi level ( ). By tuning the chemical potential from - 0.3 to + 0.3 eV, it varies rapidly and monotonically from -1.2 × 10 to 3.1 . In addition, we also find that the Te vacancy in the patterned monolayer can induce excellent HER activity. Our results not only offer a new idea to search 2D materials with large SHC, i.e., by introducing inversion-symmetry breaking vacancies in large SOC systems, but also provide a feasible system with tunable SHC (by applying gate voltage) and excellent HER activity.
二维（2D）材料因其潜在应用而备受关注。在这项工作中，我们基于第一性原理计算提出，由有序的碲空位形成的具有 Kagome 晶格的（2×2）图案化 PtTe 单层具有大且可调的自旋霍尔电导率（SHC）以及优异的析氢反应（HER）活性。这种非常规特性依赖于无自旋轨道耦合（SOC）时最高价带的 1@1 能带表示。大的 SHC 来自碲空位诱导的非中心对称结构中的 Rashba SOC。尽管它具有金属性的 SOC 能带结构，但由于存在直接带隙，ℤ 不变量定义明确且计算结果为非平凡的。在费米能级（ ）处计算得到的 SHC 高达 1.25×10 （Ω cm）。通过将化学势从 -0.3 调节到 +0.3 eV，它从 -1.2×10 迅速且单调地变化到 3.1 。此外，我们还发现图案化单层中的碲空位可诱导出优异的 HER 活性。我们的结果不仅为寻找具有大 SHC 的二维材料提供了新思路，即通过在大 SOC 系统中引入破坏反演对称性的空位，而且还提供了一个具有可调 SHC（通过施加栅极电压）和优异 HER 活性的可行体系。
