Superconductivity related to the suppression of exciton formation in 1T-TiSe2

Qing Hu; Shuxiang Xu; Xuming Guo; Hangtian Liu; Zhiyu Chen; Bosen Wang; Ran Ang

doi:10.1088/1361-648X/aba1ab

Superconductivity related to the suppression of exciton formation in 1T-TiSe₂

J Phys Condens Matter. 2020 Jul 27;32(42). doi: 10.1088/1361-648X/aba1ab.

Authors

Qing Hu¹, Shuxiang Xu², Xuming Guo¹, Hangtian Liu¹, Zhiyu Chen¹, Bosen Wang^{2

3}, Ran Ang^{1

4}

Affiliations

¹ Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People's Republic of China.
² Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
³ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China.
⁴ Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610065, People's Republic of China.

PMID: 32720648
DOI: 10.1088/1361-648X/aba1ab

Abstract

In strongly correlated electron system, the impact of elementary substitution or intercalation plays a crucial role in determining electronic ground state among various macroscopic quantum phases such as charge order and superconductivity. Here, we report that simultaneous Cu intercalation and Ta substitution at Ti site in 1T-Cu_xTi_0.8Ta_0.2Se₂induce an intrinsic electronic phase diagram, characterized by an inherent superconducting transition in thexregion of 0 ⩽x⩽ 0.12, with a maximum superconducting transition temperatureT_cof 2.5 K forx= 0.04, in contrast to the non-superconducting sample 1T-Cu_0.04TiSe₂. The increased density of free charge carriers screen the Coulomb interaction between electron-hole pairs effectively, promoting the occurrence of superconductivity favourably. Present results suggest that the Cu intercalation and the Ta substitution-induced suppression of the exciton condensation boost the superconductivity, shedding new light on the fundamental physics of the interplay between superconductivity, charge order, and electron correlation.

Keywords: charge density wave; exciton; layered transition-metal dichalcogenides; superconductivity.