Defect-induced helicity dependent terahertz emission in Dirac semimetal PtTe₂ thin films.

ABSTRACT: Nonlinear transport enabled by symmetry breaking in quantum materials has aroused considerable interest in condensed matter physics and interdisciplinary electronics. However, achieving a nonlinear optical response in centrosymmetric Dirac semimetals via defect engineering has remained a challenge. Here, we observe the helicity dependent terahertz emission in Dirac semimetal PtTe₂ thin films via the circular photogalvanic effect under normal incidence. This is activated by a controllable out-of-plane Te-vacancy defect gradient, which we unambiguously evidence with electron ptychography. The defect gradient lowers the symmetry, which not only induces the band spin splitting but also generates the giant Berry curvature dipole responsible for the circular photogalvanic effect. We d

SUBMITTER: Chen Z 

PROVIDER: S-EPMC10960839 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature