In this work, we have investigated the emergence of quantum anomalous Hall (QAH) effect in 1T-CrX2 (X = Bi, Sb) monolayers. Using a combination of first-principles and tight-binding methods, we demonstrate that the topological phase is a result of biaxial tensile strain, many-electron effects, and spin–orbit coupling. Both two-dimensional structures are ferromagnetic under strain and the phase transition from trivial to QAH is identified by nonvanishing Berry curvature with a Chern number C=2. The many-electron effects, expressed here by an effective Coulomb U parameter, play an important role in the magnetic anisotropy energy, affecting the QAH phase. Our results show that the 1T-CrX2 monolayers support large deformations, up to 25% of biaxial tensile strain, keeping their electronic, magnetic, and topological properties. This large elasticity combined with the bulk-boundary topological states, makes these 2D magnetic structures feasible to adhere on distinct surfaces being potential for spintronic applications.

中文翻译：

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调谐铁磁 1T-CrX2 （X = Bi， Sb） 单层中的量子反常霍尔效应


在这项工作中，我们研究了 1T-CrX2 （X = Bi， Sb） 单层中量子反常霍尔 （QAH） 效应的出现。使用第一性原理和紧结合方法，我们证明了拓扑相是双轴拉伸应变、多电子效应和自旋-轨道耦合的结果。两种二维结构在应变下都是铁磁性的，并且从微不足道到 QAH 的相变由 Chern 数 C=2 的不消失 Berry 曲率来识别。此处由有效的库仑 U 参数表示的多电子效应在磁各向异性能量中起重要作用，影响 QAH 相。我们的结果表明，1T-CrX2 单层支持高达 25% 的双轴拉伸应变的大变形，同时保持其电子、磁性和拓扑特性。这种大弹性与体边界拓扑状态相结合，使这些 2D 磁性结构可以粘附在不同的表面上，从而有可能用于自旋电子学应用。