paper

Ac $_{3}$ Ni $_{2}$ O $_{7}$ and La $_{2}$ $A e$ Ni $_{2}$ O $_{6}$ F ( $A e$ = Sr, Ba): Benchmark Materials for Bilayer Nickelate Superconductivity

arXiv:2403.11713

Abstract

We theoretically propose Ac $_{3}$ Ni $_{2}$ O $_{7}$ , La $_{2}$ BaNi $_{2}$ O $_{6}$ F, and La $_{2}$ SrNi $_{2}$ O $_{6}$ F compounds to be benchmark materials for bilayer nickelate superconductivity. The stable phase of Ac $_{3}$ Ni $_{2}$ O $_{7}$ and La $_{2}$ BaNi $_{2}$ O $_{6}$ F are found to be $I 4/ mmm$ without the lattice distortion caused by octahedra rotation at ambient pressure, where as the lattice distortion in La $_{2}$ SrNi $_{2}$ O $_{6}$ F can be suppressed with relatively small external pressure of 4 GPa. The magnetism, electronic structure and spin susceptibilities of Ac $_{3}$ Ni $_{2}$ O $_{7}$ are extremely close to those of La $_{3}$ Ni $_{2}$ O $_{7}$ at 30 GPa. The ground state of La $_{2}$ BaNi $_{2}$ O $_{6}$ F and La $_{2}$ SrNi $_{2}$ O $_{6}$ F are antiferromagnetically coupled checkerboard bilayer with sizable magnetic moment on Ni. In addition, the inter-layer coupling $J_{⊥}$ between Ni-bilayers in La $_{2}$ BaNi $_{2}$ O $_{6}$ F or La $_{2}$ SrNi $_{2}$ O $_{6}$ F is only $\sim$ 1/10 of that in Ac $_{3}$ Ni $_{2}$ O $_{7}$ or La $_{3}$ Ni $_{2}$ O $_{7}$ at 30 GPa. We argue that these compounds may serve as superconducting candidates at ambient pressure and can be employed to testify theoretical proposals for bilayer nickelate superconductivity.

Ac3​Ni2​O7​ and La2​AeNi2​O6​F (Ae = Sr, Ba): Benchmark Materials for Bilayer Nickelate Superconductivity

Abstract

Ac $_{3}$ Ni $_{2}$ O $_{7}$ and La $_{2}$ $A e$ Ni $_{2}$ O $_{6}$ F ( $A e$ = Sr, Ba): Benchmark Materials for Bilayer Nickelate Superconductivity