Enhanced crystal-field splitting and orbital-selective coherence induced by strong correlations in V₂O₃

Abstract

We present a study of the paramagnetic metallic and insulating phases of vanadium sesquioxide by means of the Nth order muffin-tin orbital implementation of density functional theory combined with dynamical mean-field theory. The transition is shown to be driven by a correlation-induced enhancement of the crystal-field splitting within the t_2g manifold, which results in a suppression of the hybridization between the a_1g and e_g^π bands. We discuss the changes in the effective quasiparticle band structure caused by the correlations and the corresponding self-energies. At temperatures of about 400 K, we find the a_1g orbital displays coherent quasiparticle behavior, while a large imaginary part of the self-energy and broad features in the spectral function indicate that the e_g^π orbitals are still far above their coherence temperature. The local spectral functions are in excellent agreement with recent bulk sensitive photoemission data. Finally, we also make a prediction for angle-resolved photoemission experiments by calculating momentum-resolved spectral functions.