Daily Overview: Today’s highlighted work focuses on an in-depth understanding of the electronic structure of hybrid Ruddlesden-Popper nickelates. Specifically, Ref. [1] systematically investigated the possibility of electron doping in La₃Ni₂O₇ thin films by substituting lanthanum with tetravalent elements using first-principles density functional theory calculations. The results show that cerium doping is ineffective in introducing electron carriers into the low-energy bands, whereas zirconium, hafnium, and thorium are efficient electron donors. Among them, zirconium and hafnium preferentially inject electrons into the d_{x^2−y^2}-derived band, while thorium injects more electrons into the d_{z^2}-derived band. Electron doping significantly enhances the interlayer hopping t⊥ between d_{z^2} orbitals, which is expected to increase the interlayer superexchange coupling J⊥ and thereby raise the superconducting transition temperature T_c. The study also calculated Coulomb interaction parameters using the constrained random phase approximation and identified candidate dopant elements for achieving electron-doped La₃Ni₂O₇, providing a new platform for enriching the nickelate material family and clarifying its superconducting pairing mechanism. arXiv submission processing window: 2026-08-17 00:00 to 2026-08-17 00:00 UTC.

1. Electron Doping of $\mathrm{La_3Ni_2O_7}$ Thin Films: Candidate Metal Dopants and Their Potential Impact on Superconductivity

Summary: Through first-principles density functional theory calculations, this work systematically investigates the possibility of achieving electron doping in La₃Ni₂O₇ thin films by substituting lanthanum with tetravalent elements. The results show that cerium doping can hardly introduce electron carriers effectively into the low-energy bands; in contrast, zirconium, hafnium, and thorium are efficient electron donors. Zirconium and hafnium doping preferentially inject electrons into the dx2−y2-derived band, whereas thorium doping injects more electrons into the dz2-derived band. Electron doping significantly enhances the interlayer hopping t⊥ between dz2 orbitals, thereby potentially increasing the interlayer superexchange coupling J⊥ and contributing to an elevated superconducting transition temperature Tc. The Coulomb interaction parameters are also calculated using the constrained random phase approximation. These results identify candidate dopant elements for realizing electron-doped La₃Ni₂O₇, which not only enrich the material family but also provide a new platform for clarifying the origin of superconductivity and the pairing mechanism in this system.