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 La 3 Ni 2 O 7 , the atomic structure and electronic band structure of the trilayer nickelate La 4 Ni 3 O 10 under pressure up to 44.3 GPa are investigated. A structural transition from the monoclinic P 2 1 / a space group to the tetragonal I 4/ 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 orbital rises and crosses the Fermi level at high pressures, which may give rise to possible superconductivity observed in resistance under pressure in La 4 Ni 3 O 10 . The trilayer nickelate La 4 Ni 3 O 10 shows some similarities with the bilayer La 3 Ni 2 O 7 and has unique properties, providing a new platform to investigate the underlying mechanism of superconductivity in nickelates.