Colossal Terahertz Photoresponse at Room Temperature: A Signature of Type-II Dirac Fermiology

Huang Xu; Fucong Fei; Zhiqingzi Chen; Xiangyan Bo; Zhe Sun; Xiangang Wan; Li Han; Lin Wang; Kaixuan Zhang; Jiazhen Zhang; Gang Chen; Changlong Liu; Wanlong Guo; Luhan Yang; Dacheng Wei; Fengqi Song; Xiaoshuang Chen; Wei Lu

doi:10.1021/acsnano.0c10304

Colossal Terahertz Photoresponse at Room Temperature: A Signature of Type-II Dirac Fermiology

ACS Nano. 2021 Mar 23;15(3):5138-5146. doi: 10.1021/acsnano.0c10304. Epub 2021 Feb 23.

Authors

Huang Xu^{1

2}, Fucong Fei³, Zhiqingzi Chen^{1

2}, Xiangyan Bo³, Zhe Sun⁴, Xiangang Wan³, Li Han^{1

5}, Lin Wang^{1

2}, Kaixuan Zhang^{1

5}, Jiazhen Zhang^{1

2}, Gang Chen¹, Changlong Liu^{1

6}, Wanlong Guo^{1

7}, Luhan Yang^{1

8}, Dacheng Wei⁹, Fengqi Song³, Xiaoshuang Chen^{1

7

6}, Wei Lu^{1

7}

Affiliations

¹ State Key Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu-Tian Road, Shanghai 200083, China.
² University of Chinese Academy of Sciences, No. 19A Yu-quan Road, Beijing 100049, China.
³ National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Department of Physics, Nanjing University, Nanjing 210093, China.
⁴ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China.
⁵ Department of Optoelectronic Science and Engineering, Donghua University, Shanghai 201620, China.
⁶ College of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
⁷ School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
⁸ School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
⁹ State Key Laboratory of Molecular Engineering Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, China.

PMID: 33620212
DOI: 10.1021/acsnano.0c10304

Abstract

The discovery of Dirac semimetal has stimulated bourgeoning interests for exploring exotic quantum-transport phenomena, holding great promise for manipulating the performance of photoelectric devices that are related to nontrivial band topology. Nevertheless, it still remains elusive on both the device implementation and immediate results, with some enhanced or technically applicable electronic properties signified by the Dirac fermiology. By means of Pt doping, a type-II Dirac semimetal Ir_1-xPt_xTe₂ with protected crystal structure and tunable Fermi level has been achieved in this work. It has been envisioned that the metal-semimetal-metal device exhibits an order of magnitude performance improvement at terahertz frequency when the Fermi level is aligned with the Dirac node (i.e., x ∼ 0.3) and a room-temperature photoresponsivity of 0.52 A·W^-1 at 0.12 THz and 0.45 A·W^-1 at 0.3 THz, which benefited from the excitation of type-II Dirac fermions. Furthermore, van der Waals integration with Dirac semimetals exhibits superb performance with noise equivalent power less than 24 pW·Hz^-0.5, rivaling the state-of-the-art detectors. Our work provides a route to explore the nontrivial topology of Dirac semimetal for addressing targeted applications in imaging and biomedical sensing across a terahertz gap.

Keywords: Dirac semimetal; angle-resolved photoemission spectroscopy; fermiology; terahertz detection; vdW heterostructure.