Zhang Weihua, Ding Shoubing, Zhang Jie, Cheng Zhenxiang, Wu Zhimin
School of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331, China.
Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Wollongong 2500, Australia.
Nanoscale. 2024 Sep 19;16(36):17110-17117. doi: 10.1039/d4nr00120f.
Spin-gapless semiconductors (SGSs), serving as superior alternatives to half-metals, open up new avenues in spintronics. Specifically, Weyl-point SGSs (WPSGSs) with ideal Weyl points at the Fermi energy level represent an optimal amalgamation of spintronics and topological physics. Moreover, considering spin-orbital coupling (SOC), most two-dimensional (2D) WPSGSs undergo transformation into half Chern insulators (HCIs) with the emergence of the quantum anomalous Hall effect (QAHE). The 2D I-II-V half-Heusler compounds, constituting a broad family of narrow-bandgap semiconductors with low-buckled hexagonal honeycomb crystal structures akin to silicene, aptly function as SGSs and serve as nontrivial topological parent materials. Through first-principles calculations, we propose that the LiXCrY (X = Mg, Zn, Cd; Y = P, As) monolayers, derived by substituting certain X atoms in the LiXY (X = Mg, Zn, Cd; Y = P, As) monolayers of I-II-V half-Heusler compounds with Cr atoms, emerge as potential candidates for ideal 2D WPSGSs. These monolayers exhibit stable thermodynamic properties and 100% spin polarization. With SOC taken into account, the LiXCrY monolayers transition into HCIs with a Chern number of +1, giving rise to the QAHE. These intriguing findings lay the groundwork for a promising material platform for the development of low-power spintronic and topological microelectronic devices.
自旋无隙半导体（SGSs）作为半金属的优质替代品，为自旋电子学开辟了新途径。具体而言，在费米能级具有理想外尔点的外尔点SGSs（WPSGSs）是自旋电子学与拓扑物理学的最佳融合。此外，考虑到自旋轨道耦合（SOC），大多数二维（2D）WPSGSs会随着量子反常霍尔效应（QAHE）的出现而转变为半陈绝缘体（HCIs）。二维I-II-V半赫斯勒化合物构成了一类宽带隙半导体大家族，具有类似于硅烯的低扭曲六角蜂窝晶体结构，可恰当地充当SGSs，并作为非平凡拓扑母体材料。通过第一性原理计算，我们提出，通过用Cr原子取代I-II-V半赫斯勒化合物LiXY（X = Mg、Zn、Cd；Y = P、As）单层中的某些X原子而得到的LiXCrY（X = Mg、Zn、Cd；Y = P、As）单层，有望成为理想二维WPSGSs的潜在候选材料。这些单层表现出稳定的热力学性质和100%的自旋极化。考虑到SOC时，LiXCrY单层转变为陈数为+1的HCIs，从而产生QAHE。这些有趣的发现为开发低功耗自旋电子和拓扑微电子器件奠定了一个有前景的材料平台基础。
