AI 中文总结
研究交替磁双层Fe2WS4，通过第一性原理计算表明层间滑动方向是对称性选择控制参数。对角滑动可实现铁电可切换的反常霍尔效应，轴向滑动能导致可切换的反常谷霍尔效应，确立其为控制多种特性的非易失性对称性选择器。
AI 中文摘要
交替磁体将补偿共线磁序与动量相关的自旋分裂相结合，为在无净磁化情况下将自旋和谷自由度与铁电和贝里曲率驱动的输运耦合提供了一个有前景的平台。然而，实现对这些相互交织的自由度的非易失性和选择性控制仍然是一个关键挑战。本文通过第一性原理计算表明，层间滑动方向在交替磁双层Fe2WS4中作为对称性选择控制参数。对角滑动打破反演对称性并产生两个具有相反面外极化的滑动铁电态。铁电极化的反转会切换动量相关的自旋纹理并反转反常霍尔电导率，揭示出强磁电耦合并实现铁电可切换的反常霍尔效应。相比之下，轴向滑动保持反演对称性，但打破了与X和Y谷相关的晶体对称性，导致可逆的谷极化和可切换的反常谷霍尔效应。这些结果确立了层间滑动方向作为二维交替磁双层中控制铁电、自旋纹理、谷极化和霍尔输运响应的非易失性对称性选择器。
英文摘要
Altermagnets combine compensated collinear magnetic order with momentum-dependent spin splitting, offering a promising platform for coupling spin and valley degrees of freedom with ferroelectricity and Berry-curvature driven transport in the absence of net magnetization. However, achieving nonvolatile and selective control of these intertwined degrees of freedom remains a key challenge. Here, using first-principles calculations, we show that the direction of interlayer sliding serves as a symmetry selective control parameter in altermagnetic bilayer Fe2WS4. Diagonal sliding breaks inversion symmetry and produces two sliding ferroelectric states with opposite out-of-plane polarizations. Reversal of the ferroelectric polarization switches the momentum-dependent spin texture and reverses the anomalous Hall conductivity, revealing strong magnetoelectric coupling and enabling a ferroelectrically switchable anomalous Hall effect. In contrast, axial sliding preserves inversion symmetry but breaks the crystalline symmetry relating the X and Y valleys, leading to reversible valley polarization and a switchable anomalous valley Hall effect. These results establish the direction of interlayer sliding as a nonvolatile symmetry selector for controlling ferroelectricity, spin texture, valley polarization, and Hall transport responses in two-dimensional altermagnetic bilayers.
