Multi-orbital effects in optical properties of vanadium sesquioxide

Vanadium sesquioxide, V₂O₃, boasts a rich phase diagram whose description necessitates accounting for many-body Coulomb correlations. The spectral properties of this compound have been successfully addressed within dynamical mean field theory to the extent that results of recent angle-resolved photoemission experiments have been correctly predicted. While photoemission spectroscopy probes the occupied part of the one-particle spectrum, optical experiments measure transitions into empty states and thus provide complementary information. In this work, we focus on the optical properties of V₂O₃ in its paramagnetic phases by employing our recently developed 'generalized Peierls approach'. We obtain results in overall satisfactory agreement with experiments. Further, we rationalize that the experimentally observed temperature dependence stems from the different coherence scales of the charge carriers involved.