${\mathrm{Cr}}_2{\mathrm{Te}}_3$ is a ferromagnetic, quasi-two-dimensional layered material with perpendicular magnetic anisotropy, strong spin-orbit coupling, and nontrivial band topology. The nontrivial topology results in an intrinsic anomalous Hall conductivity (AHC) that switches sign under filling and biaxial strain. Thin films can exhibit half-metallicity. Using density-functional theory combined with maximally localized Wannier functions, we reveal the physical origins of the sensitivity of the sign of the AHC to strain and filling, and we determine the effect of surface termination on the half-metallicity. We find that thin films terminated on the Te layers are the most energetically stable, but only the thin films terminated on both sides with the partially occupied Cr layers are half metals. In bulk ${\text{Cr}}_2{\text{Te}}_3$, the sensitivity of the sign of the AHC to strain and filling results from the complex Fermi surface comprised of three bands. Filling of local minima and bands near anticrossings alters the local Berry curvature, consistent with the negative-to-positive switching of the AHC. Similarly, strain depopulates a local minimum, shifts a degenerate point closer to the Fermi energy, and causes two spin-orbit split bands to reverse their order. These findings provide a physical understanding of the evolution of the Berry phase, AHC, and half-metallicity in ${\text{Cr}}_2{\text{Te}}_3$.

中文翻译：

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Cr2Te3 中贝里相和半金属性随应变、填充、厚度和表面终止的演变

${铬}_2{碲}_3$是一种铁磁准二维层状材料，具有垂直磁各向异性、强自旋轨道耦合和非平凡的能带拓扑。这种非平凡的拓扑结构会产生固有的反常霍尔电导率 (AHC)，该电导率会在填充和双轴应变下切换符号。薄膜可以表现出半金属性。利用密度泛函理论与最大局域 Wannier 函数相结合，我们揭示了 AHC 符号对应变和填充的敏感性的物理起源，并确定了表面终止对半金属性的影响。我们发现，终止于 Te 层的薄膜是最能量稳定的，但只有终止于两侧且部分占据 Cr 层的薄膜才是半金属。散装${\text{铬}}_2{\text{碲}}_3$，AHC 符号对应变和填充的敏感性源自由三个能带组成的复杂费米表面。填充局部最小值和反交叉点附近的带会改变局部贝里曲率，与 AHC 的负向正切换一致。类似地，应变会减少局部最小值，使简并点移动到更接近费米能量，并导致两个自旋轨道分裂带反转其顺序。这些发现提供了对 Berry 相、AHC 和半金属性演化的物理理解。${\text{铬}}_2{\text{碲}}_3$。