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 $\text{Ni-3}{d}_{z^2}$ to the in-plane $\text{Ni-3}{d}_{x^2-y^2}$ 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 $T_c$. Based on these findings, we reproduce the dome-shaped variation of $T_c$ 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.

Close

PrevNext

View figure in article

• Antiferromagnetism
• Doping effects
• Electron-phonon coupling
• Impurities in superconductors
• High-temperature superconductors
• Nickelates
• Density functional theory