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; Robert J Cava; Liling Sun

doi:10.1038/s41467-023-38763-4

The breakdown of both strange metal and superconducting states at a pressure-induced quantum critical point in iron-pnictide superconductors

Nat Commun. 2023 May 30;14(1):3116. doi: 10.1038/s41467-023-38763-4.

Authors

Shu Cai¹, Jinyu Zhao^{1

2}, Ni Ni^{3

4}, Jing Guo^{1

5}, Run Yang¹, Pengyu Wang^{1

2}, Jinyu Han^{1

2}, Sijin Long^{1

2}, Yazhou Zhou¹, Qi Wu¹, Xianggang Qiu^{1

2

5}, Tao Xiang^{1

2}, Robert J Cava³, Liling Sun^{6

7

8}

Affiliations

¹ Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China.
² University of Chinese Academy of Sciences, 100190, Beijing, China.
³ Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA.
⁴ Department of Physics and Astronomy, UCLA, Los Angeles, CA, 90095, USA.
⁵ Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China.
⁶ Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China. llsun@iphy.ac.cn.
⁷ University of Chinese Academy of Sciences, 100190, Beijing, China. llsun@iphy.ac.cn.
⁸ Songshan Lake Materials Laboratory, 523808, Dongguan, Guangdong, China. llsun@iphy.ac.cn.

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 Ca₁₀(Pt₄As₈)((Fe_0.97Pt_0.03)₂As₂)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.