论文标题
磁性半学中的三阶电荷传输
Third-order charge transport in a magnetic topological semimetal
论文作者
论文摘要
磁性拓扑材料及其物理特征是当前研究的重点。在这里，通过第一原理的计算和对称分析，我们揭示了现有的抗fiferromagnet Thmn2Si2中的拓扑半学状态。根据néel矢量取向，费米级附近的拓扑带交叉点形成了双节点环或两对迪拉克点，它们在自旋轨道耦合下都是四倍的脱位且强大的。这些拓扑特征会产生较大的浆果连接极化，从而提高了非线性传输效应。特别是，我们评估了三阶电流响应，该电流响应主导了横向电荷电流。我们表明，与线性响应相比，非线性响应对拓扑相变的敏感性要高得多，后者为表征磁性拓扑半学的功能提供了强大的工具。
Magnetic topological materials and their physical signatures are a focus of current research. Here, by first-principles calculations and symmetry analysis, we reveal topological semimetal states in an existing antiferromagnet ThMn2Si2. Depending on the Néel vector orientation, the topological band crossings near the Fermi level form either a double-nodal loop or two pairs of Dirac points,which are all fourfold degenerate and robust under spin-orbit coupling. These topological features produce large Berry connection polarizability, which leads to enhanced nonlinear transport effects. Particularly, we evaluate the third order current response, which dominates the transverse charge current. We show that the nonlinear response can be much more sensitive to topological phase transitions than linear response, which offers a powerful tool for characterizing magnetic topological semimetals.
