As novel states of quantum matter, quantum spin Hall (QSH) and quantum anomalous Hall (QAH) states have attracted considerable interest in condensed matter and materials science communities. Recently, a monolayer of the naturally occurring mineral jacutingaite (Pt₂HgSe₃), was theoretically proposed to be a large-gap QSH insulator and experimentally confirmed. Here, based on first-principles calculations and tight-binding modeling, we demonstrate QSH to QAH phase transition in jacutingaite by chemical functionalization with chalogen. We show that two-dimensional (2D) chalogenated jacutingaite, Pt₂HgSe₃-X (X = S, Se, Te), is ferromagnetic with Curie temperature up to 316 K, and it exhibits QAH effect with chiral edge states inside a sizeable topological gap. The physical mechanism lies in the adsorption induced transformation of the original Kane-Mele model into an effective four-band model involving (p_x, p_y) orbitals on a hexagonal lattice, so that the topological gap size can be controlled by spin–orbit coupling strength of the chalogen (0.28 eV for Pt₂HgSe₃-Te). These results not only show the promise of functionalization in orbital-engineering of 2D functional structures, but also provide an ideal and practical platform for achieving exotic topological phases for dissipationless transport and quantum computing.

中文翻译：

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功能化诱导单层jacutingaite中的量子自旋霍尔到量子异常霍尔相变

作为量子态的新态，量子自旋霍尔（QSH）和量子反常霍尔（QAH）态引起了人们对凝聚态物质和材料科学界的浓厚兴趣。近来，理论上提出将天然存在的矿物钠铝矾石（Pt ₂ HgSe ₃）的单层作为大间隙QSH绝缘体并通过实验证实。在此，基于第一性原理计算和紧密结合模型，我们通过化学试剂将变质酚与钙铝矾石从QSH转变为QAH。我们显示了二维（2D）变质的jacutingaite，Pt ₂ HgSe ₃-X（X = S，Se，Te）是铁磁性的，居里温度高达316 K，并且在相当大的拓扑间隙内，具有手性边缘态的QAH效应。物理机制在于吸附诱导的将原始Kane-Mele模型转换为包含六边形晶格上的（p _x，p _y）轨道的有效四能带模型，从而可以通过自旋轨道控制拓扑间隙的大小变通量的耦合强度（Pt ₂ HgSe ₃ -Te为0.28 eV ）。这些结果不仅表明了在二维功能结构的轨道工程中实现功能化的希望，而且为实现无耗散传输和量子计算的奇异拓扑阶段提供了理想且实用的平台。