论文标题
中心对称晶体中的几何光子拖拉效应和非线性移位电流
Geometric photon-drag effect and nonlinear shift current in centrosymmetric crystals
论文作者
论文摘要
长期以来，已知在具有反转对称性的晶体中不存在非线性偏移电流，也称为线性极化光产生的大量光伏电流。在这里，我们认为中心对称晶体中的非零移位电流可以通过光子拖拉效应激活。光子 - 拖拉移位电流从“移位电流偶极子”（表征频带间跃迁的几何量）中进行，并在中心对称晶体中表现出纯粹的横向响应。这种横向性质直接从镜像操作下的偏移量载体的伪自然角度进行，并强调了其内在的几何起源。光子 - 拖拉移位电流可以通过耦合到极性子来大大增强，并提供了一种新的和敏感的工具，以询问材料的微妙的材料间相干，而反演对称性先前被认为是通过光电探针无法访问的。
The nonlinear shift current, also known as the bulk photovoltaic current generated by linearly polarized light, has long been known to be absent in crystals with inversion symmetry. Here we argue that a non-zero shift current in centrosymmetric crystals can be activated by a photon-drag effect. Photon-drag shift current proceeds from a `shift current dipole' (a geometric quantity characterizing interband transitions) and manifests a purely transverse response in centrosymmetric crystals. This transverse nature proceeds directly from the shift-vector's pseudovector nature under mirror operation and underscores its intrinsic geometric origin. Photon-drag shift current can greatly enhanced by coupling to polaritons and provides a new and sensitive tool to interrogate the subtle interband coherences of materials with inversion symmetry previously thought to be inaccessible via photocurrent probes.
