Record high Tc element superconductivity achieved in titanium
Changling Zhang, Xin He, Chang Liu, Zhiwen Li, Ke Lu, Sijia Zhang, Shaomin Feng, Xiancheng Wang, Yi Peng, Youwen Long, Richeng Yu, Luhong Wang, Vitali B. Prakapenka, Stella Chariton, Quan Li, Haozhe Liu, Changfeng Chen, Changqing Jin
Abstract
Abstract It is challenging to search for high T c superconductivity (SC) in transition metal elements wherein d electrons are usually not favored by conventional BCS theory. Here we report experimental discovery of surprising SC up to 310 GPa with T c above 20 K in wide pressure range from 108 GPa to 240 GPa in titanium. The maximum T c onset above 26.2 K and zero resistance T c zero of 21 K are record high values hitherto achieved among element superconductors. The H c2 (0) is estimated to be ∼32 Tesla with coherence length 32 Å. The results show strong s - d transfer and d band dominance, indicating correlation driven contributions to high T c SC in dense titanium. This finding is in sharp contrast to the theoretical predications based on pristine electron-phonon coupling scenario. The study opens a fresh promising avenue for rational design and discovery of high T c superconductors among simple materials via pressure tuned unconventional mechanism.