Computational design of a new layered superconductor LaOTlF2

Abstract

A new layered compound LaOTlF₂ is designed and investigated using first-principles calculations in this work. The parent compound is an insulator with an indirect band gap of 3.88 eV. Electron-doping of the parent compound makes the material metallic. In the meantime, several lattice vibrational modes couple strongly to the conduction band, leading to a large electron–phonon coupling constant and conventional superconductivity. The highest superconducting transition temperature T_c is predicted to be approximately 8.6 K with λ about 1.25 in the optimally doped LaO_0.95F_0.05TlF₂, where λ is calculated using the Wannier interpolation technique.