Thermal decoupling in high-Tc cuprate superconductors

Abstract In unconventional high- T c cuprate superconductors, the intricate interplay between the non-ergodic bad metal 1,2 and the strange metal state 3 has remained enigmatic. Herein, we unravel this mystery using ab initio molecular dynamics (AIMD) simulations coupled with the temperature-dependent effective potential (TDEP) method. Our investigation, centered on YBa 2 Cu 3 O 7 (YBCO), provides the first simulation report on the B 1g phonon anomaly 4,5 , unveiling profound thermal decoupling induced by the bond weakening between the Ba atom and CuO 2 plane. Notably, this decoupling emerges as a pivotal underpinning behind several puzzling phenomena in high- T c superconductivity. Our results indicate that the effective temperature on the BaO plane deviates from that of the CuO 2 plane at low temperatures. Furthermore, we delineate the correlation between thermal decoupling and the Planckian dissipation, rigorously and quantitatively revealing a profound connection between linear-T resistivity, Uemura plots, and superconducting domes, which are known to be the most important unsolved mysteries of high- T c superconductivity. Our discoveries offer a revolutionary perspective on high- T c superconductivity, suggesting the potential for a transformative shift in our comprehension. Furthermore, they suggest that the autonomous emergence of low-temperature layers within materials has the potential to revolutionize industrial thermal management challenges.