Observation of Two-Dimensional Type-II Superconductivity in Bulk 3R-TaSe2 by Scanning Tunneling Spectroscopy

Xinyu Huang; Liangguang Jia; Xuan Song; Yaoyao Chen; Yanpeng Song; Kai Yang; Jian-Gang Guo; Yuan Huang; Liwei Liu; Yeliang Wang

doi:10.1021/acs.jpclett.3c01730

Observation of Two-Dimensional Type-II Superconductivity in Bulk 3R-TaSe₂ by Scanning Tunneling Spectroscopy

J Phys Chem Lett. 2023 Aug 17;14(32):7235-7240. doi: 10.1021/acs.jpclett.3c01730. Epub 2023 Aug 8.

Authors

Affiliations

¹ School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing 100081, China.
² Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.

PMID: 37552580
DOI: 10.1021/acs.jpclett.3c01730

Abstract

Here we report a low-temperature and vector-magnetic-field scanning tunneling microscopy/spectroscopy (STM/S) study on 3R-TaSe₂. The sample surface was obtained by exfoliating a bulk 3R-TaSe₂ single crystal in an ultrahigh-vacuum (UHV) chamber and then transferred in situ to STM. It was observed that the topmost layer shows a 3 × 3 charge density wave pattern at T = 4.2 K with metallic character in STS. The electronic characterization study by variable-temperature and magnetic field STS revealed that 3R-TaSe₂ behaves as a type-II superconductor. More intriguingly, such superconductivity (SC) can survive under strong in-plane magnetic fields even up to 2.5 T and out-of-plane magnetic fields up to 0.7 T, exhibiting an anisotropic superconducting property. Temperature-dependent STS showed that 3R-TaSe₂ undergoes a transition above 0.58 K. Our results may be important for understanding the intriguing SC properties of the 3R-phase van der Waals materials.