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

Zhongqiang Chen; Hongsong Qiu; Xinjuan Cheng; Jizhe Cui; Zuanming Jin; Da Tian; Xu Zhang; Kankan Xu; Ruxin Liu; Wei Niu; Liqi Zhou; Tianyu Qiu; Yequan Chen; Caihong Zhang; Xiaoxiang Xi; Fengqi Song; Rong Yu; Xuechao Zhai; Biaobing Jin; Rong Zhang; Xuefeng Wang

arXiv · 2310.09989

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

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Abstract

Nonlinear transport enabled by symmetry breaking in quantum materials has aroused considerable interest in condensed matter physics and interdisciplinary electronics. However, the nonlinear optical response in centrosymmetric Dirac semimetals via the defect engineering has remained highly challenging. Here, we observe the helicity-dependent terahertz (THz) emission in Dirac semimetal PtTe2 thin films via circular photogalvanic effect (CPGE) under normal incidence. This is activated by artificially controllable out-of-plane Te-vacancy defect gradient, which is unambiguously evidenced by the electron ptychography. The defect gradient lowers the symmetry, which not only induces the band spin splitting, but also generates the giant Berry curvature dipole (BCD) responsible for the CPGE. Such BCD-induced helicity-dependent THz emission can be manipulated by the Te-vacancy defect concentration. Furthermore, temperature evolution of the THz emission features the minimum of the THz amplitude due to the carrier compensation. Our work provides a universal strategy for symmetry breaking in centrosymmetric Dirac materials for efficient nonlinear transport and facilitates the promising device applications in integrated optoelectronics and spintronics.

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Zhongqiang Chen, Hongsong Qiu, Xinjuan Cheng, Jizhe Cui, Zuanming Jin, Da Tian, Xu Zhang, Kankan Xu, Ruxin Liu, Wei Niu, Liqi Zhou, Tianyu Qiu, Yequan Chen, Caihong Zhang, Xiaoxiang Xi, Fengqi Song, Rong Yu, Xuechao Zhai, Biaobing Jin, Rong Zhang, Xuefeng Wang. 2023-10-16. Defect-induced helicity-dependent terahertz emission in Dirac semimetal PtTe2 thin films. https://arxiv.org/abs/2310.09989

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