Theoretical investigation of superconductivity in trilayer square-planar nickelates

Emilian M. Nica; Jyoti Krishna; Rong Yu; Qimiao Si; Antia S. Botana; Onur Erten

doi:10.1103/PhysRevB.102.020504

paper

Theoretical investigation of superconductivity in trilayer square-planar nickelates

arXiv:2003.09132 · doi:10.1103/PhysRevB.102.020504

Abstract

The discovery of superconductivity in Sr-doped NdNiO $_{2}$ is a crucial breakthrough in the long pursuit for nickel oxide materials with electronic and magnetic properties similar to those of the cuprates. NdNiO $_{2}$ is the infinite-layer member of a family of square-planar nickelates with general chemical formula R $_{n + 1}$ Ni $_{n}$ O $_{2 n + 2}$ (R = La, Pr, Nd, $n = 2, 3, ...\infty$ ). In this letter, we investigate superconductivity in the trilayer member of this series (R $_{4}$ Ni $_{3}$ O $_{8}$ ) using a combination of first-principles and $t - J$ model calculations. R $_{4}$ Ni $_{3}$ O $_{8}$ compounds resemble cuprates more than RNiO $_{2}$ materials in that only Ni- $d_{x^{2} - y^{2}}$ bands cross the Fermi level, they exhibit a largely reduced charge transfer energy, and as a consequence superexchange interactions are significantly enhanced. We find that the superconducting instability in doped R $_{4}$ Ni $_{3}$ O $_{8}$ compounds is considerably stronger with a maximum gap about four times larger than that in Sr $_{0.2}$ Nd $_{0.8}$ NiO $_{2}$ .

16 pages, 7 figures