Role of hydrogen impurities in the high-Tc superconductivity of infinite-layer nickelates

Abstract

H impurities have been found to be critical for the emergence of superconductivity in nickelate superconductors, but the nature of H-induced superconductivity in nickelates remains highly controversial. In this work, using first-principles calculations and cluster expansion models with Monte Carlo simulations, we demonstrate that H impurities can effectively facilitate the charge transfer from the out-of-plane Ni-3dz2 to the in-plane Ni-3dx2−y2 orbitals, thereby enhancing the in-plane nearest-neighbor Ni-Ni antiferromagnetic (AFM) exchange. Similar to cuprate superconductivity, this in-plane AFM correlation significantly enhances the electron-phonon (el-ph) coupling strength of the in-plane O breathing mode and consequently increases the superconducting critical temperature Tc. Based on these findings, we reproduce the dome-shaped variation of Tc in the H-doping phase diagram with the AFM-assisted el-ph coupling mechanism. Our finding provides valuable insights into the critical role of H impurities and contributes to a fundamental understanding of H-induced superconductivity in nickelate superconductors.

Source-reported materials — not catalogue approval

Similar papers