论文标题

通用Weyl半法的磁光电导率

Magneto-optical conductivity in generic Weyl semimetals

论文作者

Stålhammar, Marcus, Larana-Aragon, Jorge, Knolle, Johannes, Bergholtz, Emil J.

论文摘要

已经提出了对Weyl半法的磁光学研究,作为一种多功能工具,用于观察包括手性Landau水平在内的候选材料中的低能量Weyl Fermions。但是,以前的理论结果仅限于Weyl节点周围的线性化状态,并且与实验发现不一致。在这里,我们在存在与光谱的倾斜的外部磁场的情况下得出了通用Weyl半度值的磁光电导率的封闭形式表达式。该系统被视为在两个方向上具有线性分散,而倾斜方向可以由任何任意连续可区分的函数组成。然后,该一般计算用于分析评估Weyl半金属的磁光电导率,在动量中扩展到立方顺序。特别是,研究了具有任意倾斜的系统以及托管琐事费米口袋的系统。动量中的高阶项关闭了II型制度中的费米口袋,在评估磁光电导率时消除了对非物理截止的需求。至关重要的是,考虑到封闭的过度倾斜和其他琐碎的费米口袋的能力使我们能够将模型系统更接近实际的材料处理,我们提出了一个简单的解释,为什么寄生琐碎的琐事费米口袋的存在可以掩盖磁电流电导率测量中Weyl Fermions的特征性标志。

Magneto-optical studies of Weyl semimetals have been proposed as a versatile tool for observing low-energy Weyl fermions in candidate materials including the chiral Landau level. However, previous theoretical results have been restricted to the linearized regime around the Weyl node and are at odds with experimental findings. Here, we derive a closed form expression for the magneto-optical conductivity of generic Weyl semimetals in the presence of an external magnetic field aligned with the tilt of the spectrum. The systems are taken to have linear dispersion in two directions, while the tilting direction can consist of any arbitrary continuously differentiable function. This general calculation is then used to analytically evaluate the magneto-optical conductivity of Weyl semimetals expanded to cubic order in momentum. In particular, systems with arbitrary tilt, as well as systems hosting trivial Fermi pockets are investigated. The higher-order terms in momentum close the Fermi pockets in the type-II regime, removing the need for unphysical cutoffs when evaluating the magneto-optical conductivity. Crucially, the ability to take into account closed over-tilted and additional trivial Fermi pockets allows us to treat model systems closer to actual materials and we propose a simple explanation why the presence of parasitic trivial Fermi pockets can mask the characteristic signature of Weyl fermions in magneto-optical conductivity measurements.

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