论文标题
在圆环形的费米表面上的异常Andreev反射
Anomalous Andreev Reflection on a Torus-Shaped Fermi Surface
论文作者
论文摘要
Andreev反射（AR）是指在正常金属螺旋体界面处的电子孔转换。在具有球形费米表面的三维金属中，随着粒子速度的所有三个（单个）成分的符号逆转，可能会发生复古（镜面）AR。在这里，我们预测了一种新型的AR类型，具有两个速度成分的反转，称为“异常 - 区域对象Andreev反射”（AAR），可以在带有圆环形的费米表面的一类材料中实现，例如掺杂的Nodal线半径。对于垂直于界面的环形圆圈，费米圆环将AR通道加倍并生成多个AR过程。特别是，发现AAR和复古AR分别在光和重型兴奋剂方面占主导地位。我们表明，与复古AR的峰结构相比，AAR明显表现为空间分辨的非局部电导的脊结构。我们的工作为AR光谱学开辟了新的途径，并提供了圆环形的费米表面的清晰运输标志。
Andreev reflection (AR) refers to the electron-hole conversion at the normal metal-superconductor interface. In a three-dimensional metal with spherical Fermi surface, retro (specular) AR can occur with the sign reversal of all three (a single) components of particle velocity. Here, we predict a novel type of AR with the inversion of two velocity components, dubbed "anomalous-trajectory Andreev reflection" (AAR), which can be realized in a class of materials with torus-shaped Fermi surface, such as doped nodal line semimetals. For its toroidal circle perpendicular to the interface, the Fermi torus doubles the AR channels and generates multiple AR processes. In particular, the AAR and retro AR are found to dominate electron transport in the light and heavy doping regimes, respectively. We show that the AAR visibly manifests as a ridge structure in the spatially resolved nonlocal conductance, in contrast to the peak structure for the retro AR. Our work opens a new avenue for the AR spectroscopy and offers a clear transport signature of torus-shaped Fermi surface.
