Structural transition, electric transport, and electronic structures in the compressed trilayer nickelate La₄Ni₃O₁₀

Atomic structure and electronic band structure are fundamental properties for understanding the mechanism of superconductivity. Motivated by the discovery of pressure-induced high-temperature superconductivity at 80 K in the bilayer Rud-dlesden-Popper nickelate La₃Ni₂O₇, the atomic structure and electronic band structure of the trilayer nickelate La₄Ni₃O₁₀ under pressure up to 44.3 GPa are investigated. A structural transition from the monoclinic P2₁/a space group to the tetragonal I4/mmm around 12.6–13.4 GPa is identified, accompanied by a drop of resistance below 7 K. Density functional theory calculations suggest that the bonding state of Ni \(3{d_{{z^2}}}\) $$3d_{z^2}$$ orbital rises and crosses the Fermi level at high pressures, which may give rise to possible superconductivity observed in resistance under pressure in La₄Ni₃O₁₀. The trilayer nickelate La₄Ni₃O₁₀ shows some similarities with the bilayer La₃Ni₂O₇ and has unique properties, providing a new platform to investigate the underlying mechanism of superconductivity in nickelates.