Charge density functional plus U calculation of lacunar spinel GaM₄Se₈(M = Nb, Mo, Ta, and W)

Department of Physics, KAIST - Daejeon 34141, Republic of Korea

Received: 5 October 2018
Accepted: 8 February 2019

Abstract

Charge density functional plus U calculations are carried out to examine the validity of molecular J_eff = 1/2 and 3/2 states in lacunar spinel GaM₄Se₈ (M = Nb, Mo, Ta, and W). With LDA (spin-unpolarized local density approximation)+U, which has recently been suggested as a more desirable choice than LSDA (local spin density approximation)+U, we examine the band structure in comparison with the previous prediction based on the spin-polarized version of functional and with the prototypical J_eff = 1/2 material Sr₂IrO₄. It is found that the previously suggested J_eff = 1/2 and 3/2 band characters remain valid still in LDA+U calculations while the use of charge-only density causes some minor differences. Our result provides further support for the novel molecular J_eff state in this series of materials, which can hopefully motivate the future exploration toward its verification and the further search for new functionalities.