标题： 由半导体和半金属中k线性项引起的光电流 显示英文标题

标题： Photocurrents induced by k-linear terms in semiconductors and semimetals

摘要： 我们开发了一个六带$\mathbf{k} \cdot \mathbf{p}$模型来描述手性多重半金属（如 RhSi）的电子结构和光学响应。 通过不变量方法，我们构建了描述布里渊区$\Gamma$点附近态的有效哈密顿量，其中考虑了自旋-轨道耦合和$\mathbf{k}$线性 Rashba 项，这些对圆光整流效应至关重要。 该模型使用紧束缚计算进行参数化。 我们计算了带间吸收光谱，在低能区域表现出与频率线性相关的特点，并在自旋-轨道分裂能量附近显示出共振特征。 此外，我们计算了圆光整流效应。 与之前的研究一致，低频下的电流产生率表现出由有效拓扑电荷的普遍值$|\mathcal{C}| = 4$所决定的量子化低频响应。 我们的结果为理解 Rashba 耦合和拓扑在多重手性半金属光电特性中的作用提供了分析框架。 显示英文摘要

摘要： We develop a six-band $\mathbf{k} \cdot \mathbf{p}$ model to describe the electronic structure and optical response of chiral multifold semimetals, such as RhSi. By means of invariants method we construct the effective Hamiltonian describing the states near the $\Gamma$-point of the Brillouin zone where the spin-orbit coupling and $\mathbf{k}$-linear Rashba terms, which are crucial for circular photogalvanic effect, are taken into account. The model is parameterized using tight-binding calculations. We compute the interband absorption spectrum, showing a linear-in-frequency dependence at low energies and a resonant feature near the spin-orbit splitting energy. Furthermore, we calculate the circular photogalvanic effect. In agreement with previous works the current generation rate at low frequencies exhibits a quantized low-frequency response, governed by the universal value $|\mathcal{C}| = 4$ for the effective topological charge. Our results provide an analytical framework for understanding the role of Rashba coupling and topology in the optoelectronic properties of multifold chiral semimetals.