The breakdown of both strange metal and superconducting states at a pressure-induced quantum critical point in iron-pnictide superconductors
Shu Cai, Jinyu Zhao, Ni Ni, Jing Guo, Run Yang, Pengyu Wang, Jinyu Han, Sijin Long, Yazhou Zhou, Qi Wu, Xianggang Qiu, Tao Xiang, R. J. Cava, Liling Sun
Abstract
Abstract Here we report the first observation of the concurrent breakdown of the strange metal (SM) normal state and superconductivity at a pressure-induced quantum critical point in Ca 10 (Pt 4 As 8 )((Fe 0.97 Pt 0.03 ) 2 As 2 ) 5 superconductor. We find that, upon suppressing the superconducting state, the power exponent ( α ) changes from 1 to 2, and the slope of the temperature-linear resistivity per FeAs layer ( A □ ) gradually diminishes. At a critical pressure, A □ and superconducting transition temperature ( T c ) go to zero concurrently, where a quantum phase transition from a superconducting state with a SM normal state to a non-superconducting Fermi liquid state occurs. Scaling analysis reveals that the change of A □ with T c obeys the relation of T c ~ ( A □ ) 0.5 , similar to what is seen in other chemically doped unconventional superconductors. These results suggest that there is a simple but powerful organizational principle of connecting the SM normal state with the high- T c superconductivity.