2025/03/17 by Shi, Lei, Luo, Ying, Wu, Wei +1 · 1 citation
#FOS: Physical sciences #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2503.13197
The recent discovery of pressure-induced superconductivity in La3Ni2O7 has established a novel platform for studying unconventional superconductors. However, achieving superconductivity in this system currently requires relatively high pressures. In this study, we propose a chemical pressure strategy via Sr substitution to stabilize high-Tc superconductivity in La3Ni2O7 under ambient conditions.Using density functional theory (DFT) calculations, we systematically investigate the structural and electronic properties of Sr-doped La3-xSrxNi2O7 (x = 0.25, 0.5, 1) at ambient pressure and identify two dynamically stable phases:La2.5Sr0.5Ni2O7 and La2SrNi2O7.Our calculations reveal that both phases exhibit metallization of the σ-bonding bands dominated by Ni-dz2 orbitals-a key feature associated with high-Tc superconductivity, as reported in the high-pressure phase of La3Ni2O7. Further analysis using tight-binding models shows that the key hopping parameters in La2.5Sr0.5Ni2O7 and La2SrNi2O7 closely resemble those of La3Ni2O7 under high pressure, indicating that strong super-exchange interactions between interlayer Ni-dz2 orbitals are preserved. These findings suggest that Sr-doped La3Ni2O7 is a promising candidate for realizing high-Tcsuperconductivity at ambient pressure.