Abstract
In this paper we present a comparative investigation of the electronic structures of and obtained within a combination of density functional theory and cluster-dynamical mean-field theory calculations. We investigate the role of dynamic electronic correlations on the electronic structure of the metallic and insulating phases of and , with a focus on the mechanism responsible for the gap opening in the insulating phases. For the rutile metallic phases of both oxides, we obtain that electronic correlations lead to a strong renormalization of the subbands, as well as the emergence of incoherent Hubbard subbands, signaling that electronic correlations are also important in the metallic phase of . Interestingly, we find that nonlocal dynamic correlations do play a role in the gap formation of the [body-centered-tetragonal (bct)] insulating phase of , by a similar physical mechanism as that recently proposed by us in the case of the monoclinic () dimerized phase of [Phys. Rev. Lett. 117, 056402 (2016)]. Although the effect of nonlocal dynamic correlations in the gap opening of bct phase is less important than in the ( and ) monoclinic phases of , their presence indicates that the former is not a purely Peierls-type insulator, as it was recently proposed.
- Received 10 July 2017
DOI:https://doi.org/10.1103/PhysRevB.96.195102
©2017 American Physical Society