Abstract
We perform a time-resolved optical study of SrIrO to understand the influence of magnetic ordering on the low energy electronic structure of a strongly spin-orbit coupled 1/2 Mott insulator. By studying the recovery dynamics of photoexcited carriers, we find that upon cooling through the Néel temperature the system evolves continuously from a metal-like phase with fast (50 fs) and excitation density independent relaxation dynamics to a gapped phase characterized by slower (500 fs) excitation density-dependent bimolecular recombination dynamics, which is a hallmark of a Slater-type metal-to-insulator transition. However our data indicate that the high energy reflectivity associated with optical transitions into the unoccupied 1/2 band undergoes the sharpest upturn at , which is consistent with a Mott-Hubbard type metal-to-insulator transition involving spectral weight transfer into an upper Hubbard band. These findings show SrIrO to be a unique system in which Slater- and Mott-Hubbard-type behaviors coexist and naturally explain the absence of anomalies at in transport and thermodynamic measurements.
- Received 20 March 2012
DOI:https://doi.org/10.1103/PhysRevB.86.035128
©2012 American Physical Society