Electrically and magnetically switchable nonlinear photocurrent in РТ-symmetric magnetic topological quantum materials
Electrically and magnetically switchable nonlinear photocurrent in РТ-symmetric magnetic topological quantum materials
复制标题
DOI：
10.1038/s41524-020-00462-9
复制
发表时间：
2020-12
影响因子：
9.7
通讯作者：
Hua Wang;Xiaofeng Qian
中科院分区：
文献类型：
--
作者：
Hua Wang;Xiaofeng Qian
时间反转不变非中心对称系统中的非线性光电流引起了人们的极大兴趣。在这里，我们提出了两种新型二阶非线性直接光电流作为法向位移光电流（NSC）和法向注入光电流（NIC）的对应物，即时间反演对称和反演对称破缺系统中的磁位移光电流（MSC）和磁注入光电流（MIC）。我们表明，MSC 主要受位移矢量和带间 Berry 曲率控制，而 MIC 主要受吸收强度和时间反演点群速度差的不对称性控制。 MSC和MIC可以分别由圆偏振光和线偏振光诱导，不对称系统具有和被单独破坏。以对称磁性拓扑量子材料双层反铁磁（AFM）MnBiTea为例，我们预测在太赫兹频率范围内存在大MIC，它可以通过时间反转自旋排序在两个AFM状态之间磁性切换。虽然 NSC 在对称系统中消失，但外部电场打破了对称性并实现了可以电切换的大 NSC 响应。 MIC 和 NSC 在线性/偏振光下彼此垂直，并且在电场下高度可调，从而产生低至几个太赫兹范围的巨大非线性光电流响应。它表明双层 AFM MnBiTea 是一个具有丰富太赫兹和磁光电子应用的可调平台。目前的工作表明，非线性光电流为破译磁性结构和相互作用提供了强大的工具，对于探测和理解磁性拓扑量子材料特别有效。
Nonlinear photocurrent in time-reversal invariant noncentrosymmetric systems have attracted substantial interest. Here we propose two new types of second-order nonlinear direct photocurrent as the counterpart of normal shift photocurrent (NSC) and normal injection photocurrent (NIC), namely magnetic shift photocurrent (MSC) and magnetic injection photocurrent (MIC) in time-reversal symmetry and inversion symmetry broken system. We show that MSC is mainly governed by shift vector and interband Berry curvature, and MIC is dominated by absorption strength and asymmetry of the group velocity difference at time-reversedpoints. MSC and MIC can be induced by circularly and linearly polarized light, respectively, in-symmetric systems withandbeing individually broken. Taking-symmetric magnetic topological quantum material bilayer antiferromagnetic (AFM) MnBiTeas an example, we predict the presence of large MIC in the terahertz frequency regime which can be magnetically switched between two AFM states with time-reversed spin orderings. While NSC vanishes in-symmetric systems, external electric field breakssymmetry and enables large NSC response which can be electrically switched. MIC and NSC are perpendicular to each other upon linearly/-polarized light, and are highly tunable under electric field, resulting in giant nonlinear photocurrent response down to a few THz regime. It suggests bilayer AFM MnBiTeas a tunable platform with rich THz and magneto-optoelectronic applications. The present work reveals that nonlinear photocurrent provides a powerful tool for deciphering magnetic structures and interactions, particularly fruitful for probing and understanding magnetic topological quantum materials.