表面-体态杂化增强GaAs(110)中的贝里曲率偶极子
Surface-bulk hybridization enhances the Berry curvature dipole in GaAs(110)
- Institute for Theoretical Solid State Physics, IFW Dresden（德累斯顿亥姆霍兹中心IFW凝聚态物理理论研究所）
- Centro Atómico Bariloche, Instituto de Nanociencia y Nanotecnología (CNEA-CONICET)（巴里洛切原子中心，纳米科学与技术研究所（阿根廷核能委员会-国家科学研究委员会））
- Instituto Balseiro（巴尔塞罗研究所）
- Würzburg-Dresden Cluster of Excellence ctd.qmat（维尔茨堡-德累斯顿卓越集群ctd.qmat）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
通过第一性原理计算，发现表面弛豫促进GaAs(110)表面态与体态杂化，产生贝里曲率热点，从而增强表面贝里曲率偶极子。
AI中文摘要：
晶体边界处的对称性破缺能够引发在体相中被禁止的电子响应。在此，我们利用第一性原理计算研究了GaAs(110)表面的贝里曲率偶极子（BCD）。尽管由于对称性约束，体相GaAs中的BCD为零，但降低的表面对称性允许有限的偶极子存在。我们表明，表面弛豫促进了体态与表面态之间的杂化，这强烈影响了表面BCD。具体而言，在未弛豫的 slabs 中，BCD主要来源于位于投影体带隙内的指数局域表面态之间的带间耦合。表面弛豫将这些态移入体连续谱的能量范围，将其转变为表面共振态，并促进与类体态的杂化。这种杂化产生了显著的贝里曲率热点，导致BCD整体增强。我们的结果强调了表面弛豫对于准确描述表面-体态杂化的重要性，而这种杂化在晶体边界的贝里曲率驱动响应中起着关键作用。
英文摘要：
Symmetry breaking at crystalline boundaries can enable electronic responses that are forbidden in the bulk. Here, we investigate the Berry curvature dipole (BCD) at GaAs(110) surfaces using first-principles calculations. While the BCD vanishes in bulk GaAs due to symmetry constraints, the reduced surface symmetry permits a finite dipole. We show that surface relaxation promotes hybridization between bulk and surface states, which strongly influences the surface BCD. Specifically, in unrelaxed slabs, the BCD arises predominantly from interband coupling among exponentially localized surface states lying within the projected bulk band gap. Surface relaxation shifts these states into the energy range of the bulk continuum, transforming them into surface resonances and promoting hybridization with bulk-like states. This hybridization generates pronounced Berry-curvature hot spots, resulting in an overall enhancement of the BCD. Our results highlight the importance of surface relaxation for accurately describing surface--bulk hybridization, which in turn plays a key role in Berry-curvature-driven responses at crystalline boundaries.
