Pressure-Induced Superconductivity in the Charge-Density-Wave Compound LaTe 2–x Sb x (x = 0 and 0.4)

• Published in: Chinese physics letters Vol. 40; no. 10; p. 107402
• Main Authors: Chen 陈, Xu 旭, Sun 孙, Pei-han 培函, Xie 谢, Zhenkai 圳楷, Meng 孟, Fanqi 繁琦, Pei 裴, Cuiying 翠颖, Qi 齐, Yanpeng 彦鹏, Ying 应, Tianping 天平, Liu 刘, Kai 凯, Guo 郭, Jian-gang 建刚, Chen 陈, Xiaolong 小龙
• Format: Journal Article
• Language: English
• Published: 01.10.2023
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/40/10/107402

Magnetic CeTe 2 achieving superconductivity under external pressure has received considerable attention. The intermingling of 4 f and 5 d electrons from Ce raised the speculation of an unconventional pairing mechanism arising from magnetic fluctuations. Here, we address this speculation using a nonmagnetic 4 f -electron-free LaTe 2 as an example. No structural phase transition can be observed up to 35 GPa in the in situ synchrotron diffraction patterns. Subsequent high-pressure electrical measurements show that LaTe 2 exhibits superconductivity at 20 Gpa with its T c (4.5 K) being two times higher than its Ce-counterpart. Detailed theoretical calculations reveal that charge transfer from the 4 p orbitals of the planar square Te–Te network to the 5 d orbitals of La is responsible for the emergence of superconductivity in LaTe 2 , as confirmed by Hall experiments. Furthermore, we study the modulation of q CDW by Sb substitution and find a record high T c onset ∼ 6.5 K in LaTe 1.6 Sb 0.4 . Our work provides an informative clue to comprehend the role of 5 d –4 p hybridization in the relationship between charge density wave (CDW) and superconductivity in these RETe 2 (RE = rare-earth elements) compounds.