杂质作为有隙双带模型中贝里曲率和波函数缠绕的探针
Impurity as a probe of Berry curvature and wavefunction winding in gapped two-band models
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides（巴黎萨克雷大学，法国国家科学研究中心，固体物理实验室）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出利用杂质附近的准粒子干涉，通过局域态密度探测有隙双带模型中的贝里曲率和波函数缠绕，并建立了二者与能带参数的联系。
AI中文摘要：
我们探索了利用杂质附近准粒子干涉来提取能带非局域性质的可能性。聚焦于具有多谷系统的双带最小描述，我们展示了由非磁性杂质诱导的局域态密度（LDOS）能够有效地探测每个谷局域的贝里曲率和波函数缠绕。我们分析了基于狄拉克、半狄拉克、二次接触和高阶接触能量色散的有隙模型，在存在点状势散射体的情况下。我们发现，对于足够强的杂质势，围绕杂质的等高线上的LDOS明确显示波函数缠绕数，这与无隙狄拉克型色散的情况形成对比，在后者中缠绕可能被径向方向的LDOS振荡所掩盖。我们还建立了谷内局域动量依赖的贝里曲率与波函数缠绕数和能量色散参数之间的一般联系，从而使局域贝里曲率可以直接从光谱LDOS信息中观测到。
英文摘要：
We explore the possibility of using quasiparticle interference near impurities to extract non-local properties of bands. Focusing on the minimal two-band description of a system with multiple valleys, we show that the local density of states (LDOS) induced by non-magnetic impurities can effectively probe both the Berry curvature and the wavefunction winding, locally in each valley. We analyze gapped models based on Dirac, semi-Dirac, quadratic touching, and higher-order touching energy dispersions, in presence of a point-like potential scatterer. We find that for strong enough impurity potentials the LDOS along a contour around the impurity unambiguously shows the wavefunction winding number, in contrast to the case of gapless Dirac-like dispersions where the winding can be precluded by LDOS oscillations in the radial direction. We also establish a general connection between, on the one hand, the Berry curvature as a function of momentum locally in a valley, and on the other hand, the wavefunction winding number and the energy dispersion parameters, making hence the local Berry curvature directly observable from spectroscopic LDOS information.
