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

doi:10.1038/s41467-024-46821-8

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

Nat Commun. 2024 Mar 23;15(1):2605. doi: 10.1038/s41467-024-46821-8.

Authors

Zhongqiang Chen^#¹, Hongsong Qiu^#², Xinjuan Cheng^#³, Jizhe Cui⁴, Zuanming Jin⁵, Da Tian², Xu Zhang¹, Kankan Xu¹, Ruxin Liu¹, Wei Niu¹, Liqi Zhou⁶, Tianyu Qiu⁷, Yequan Chen¹, Caihong Zhang², Xiaoxiang Xi⁷, Fengqi Song⁷, Rong Yu⁴, Xuechao Zhai⁸, Biaobing Jin^{9

10}, Rong Zhang^{11

12}, Xuefeng Wang¹³

Affiliations

¹ Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, State Key Laboratory of Spintronics Devices and Technologies, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China.
² Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, MOE Key Laboratory of Optoelectronic Devices and Systems with Extreme Performances, Nanjing University, 210093, Nanjing, China.
³ Department of Applied Physics, MIIT Key Laboratory of Semiconductor Microstructures and Quantum Sensing, Nanjing University of Science and Technology, 210094, Nanjing, China.
⁴ School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
⁵ Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, University of Shanghai for Science and Technology, 200093, Shanghai, China.
⁶ College of Engineering and Applied Sciences, Nanjing University, 210093, Nanjing, China.
⁷ State Key Laboratory of Solid State Microstructures, School of Physics, Nanjing University, 210093, Nanjing, China.
⁸ Department of Applied Physics, MIIT Key Laboratory of Semiconductor Microstructures and Quantum Sensing, Nanjing University of Science and Technology, 210094, Nanjing, China. zhaixuechao@njust.edu.cn.
⁹ Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, MOE Key Laboratory of Optoelectronic Devices and Systems with Extreme Performances, Nanjing University, 210093, Nanjing, China. bbjin@nju.edu.cn.
¹⁰ Purple Mountain Laboratories, 211111, Nanjing, China. bbjin@nju.edu.cn.
¹¹ Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, State Key Laboratory of Spintronics Devices and Technologies, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China. rzhang@nju.edu.cn.
¹² Department of Physics, Xiamen University, 361005, Xiamen, China. rzhang@nju.edu.cn.
¹³ Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, State Key Laboratory of Spintronics Devices and Technologies, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China. xfwang@nju.edu.cn.

^# Contributed equally.

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 demonstrate that the THz emission can be manipulated by the Te-vacancy defect concentration. Furthermore, the temperature evolution of the THz emission features a minimum in the THz amplitude due to carrier compensation. Our work provides a universal strategy for symmetry breaking in centrosymmetric Dirac materials for efficient nonlinear transport.

Abstract

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