Twodimensional (2D) Dirac states with linear dispersion have been observed in graphene and on the surface of topological insulators. 2D Dirac states discovered so far are exclusively pinned at highsymmetry points of the Brillouin zone, for example, surface Dirac states at
Nonlinear photocurrent in timereversal invariant noncentrosymmetric systems such as ferroelectric semimetals sparked tremendous interest of utilizing nonlinear optics to characterize condensed matter with exotic phases. Here we provide a microscopic theory of two types of secondorder nonlinear direct photocurrents, magnetic shift photocurrent (MSC) and magnetic injection photocurrent (MIC), as the counterparts of normal shift current (NSC) and normal injection current (NIC) in timereversal symmetry and inversion symmetry broken systems. 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 timereversed ±
 Award ID(s):
 1753054
 Publication Date:
 NSFPAR ID:
 10206257
 Journal Name:
 npj Computational Materials
 Volume:
 6
 Issue:
 1
 ISSN:
 20573960
 Publisher:
 Nature Publishing Group
 Sponsoring Org:
 National Science Foundation
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