The effect of Carrier Doping and Thickness on the Electronic Structures of La₃Ni₂O₇ Thin Films

The discovery of high-temperature superconductivity in bilayer nickelate La₃Ni₂O₇ under high-pressure conditions has spurred extensive efforts to stabilize superconductivity at ambient pressure. Recently, the realization of superconductivity in compressively strained La₃Ni₂O₇ thin films grown on the SrLaAlO₄ substrates, with a Tc exceeding 40 K, represents a significant step toward this goal. Here, we investigate the influence of film thickness and carrier doping on the electronic structure of The effect of Carrier Doping and Thickness on the Electronic Structures of La₃Ni₂O₇ Thin Films thin films, ranging from 0.5 to 3 unit cells (UC), using first-principles calculations. For a 2UC film with an optimal doping concentration of 0.3 hole per formula unit (0.15 hole/Ni), the Ni-d_z² interlayer bonding state crosses the Fermi level, resulting in the formation of γ pockets at the Fermi surface. These findings align with angle-resolved photoemission spectroscopy (ARPES) experimental data. Our results provide theoretical validation for the recent experimental discovery of ambient-pressure superconductivity in La₃Ni₂O₇ thin films and underscore the significant impact of film thickness and carrier doping on electronic property modulation.