论文标题
Weyl/Multi-Weyl半金属的I型和II型相的磁光电导率
Magneto-optical conductivity in the type-I and type-II phases of Weyl/multi-Weyl semimetals
论文作者
论文摘要
磁光电导率是一个经过广泛研究的运输系数，可用于理解和表征磁场下材料的行为。使用Kubo公式，我们计算电导率张量$σ_{μν} $横向到均匀磁场$ \ Mathbf B $的组件，用于多翼半度的单个节点（单极电荷$ J $等于两个或三个）。我们还包括Weyl半学（$ j = 1 $）的结果，并确定电导率曲线中的峰值，这在早期的研究中未报告。在我们的分析中，我们探讨了Weyl/Multi-Weyl锥的倾斜度如何影响$σ_{μν} $，重点是I类和II阶段。所有这些系统都有沿倾斜轴的线性摩膜内分散剂，该轴被选为与$ \ Mathbf b $保持一致的。在II型阶段中，开放的费米口袋作为低能有效连续模型的伪像，它们忽略了实际带结构的高阶动量术语。因此，我们用立方术语补充了线性功率项，该项可以关闭费米口袋，从而消除了对动量积分的任何临时截止的需求。我们的结果表明，$σ_{μν} $的吸收部分显示了多个峰作为频率的函数，其位置由能量尺度$ \ sim | \ Mathbf B |^{J/2} $确定。
Magneto-optical conductivity is a very widely studied transport coefficient, useful to understand and characterize the behaviour of materials under magnetic fields. Using the Kubo formula, we compute the components of the conductivity tensor $σ_{μν}$ transverse to a uniform magnetic field $\mathbf B$, for a single node of a multi-Weyl semimetal (with monopole charge $J$ equal to two or three). We also include the results for a Weyl semimetal (with $J=1$), and identify peaks in the conductivity profile which were not reported in earlier studies. In our analysis, we explore how the tilting of the Weyl/multi-Weyl cone affects $σ_{μν}$, focussing on both type-I and type-II phases. All these systems have a linear-in-momentum dispersion along the tilting axis, which is chosen to align with $\mathbf B$. In the type-II phases, open Fermi pockets appear as artifacts of the low-energy effective continuum models, which ignore higher-order momentum terms of the actual bandstructures. Hence, we supplement the linear power term with a cubic term, which closes the Fermi pockets, thus eliminating any need for an ad hoc cutoff for the momentum integrals. Our results reveal that the absorptive parts of $σ_{μν}$ display multiple peaks as functions of the frequency, whose locations are determined by an energy scale $\sim |\mathbf B|^{J/2} $.
