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TT: Fachverband Tiefe Temperaturen
TT 94: Low-Dimensional Systems: Oxide Hetero-Interfaces
TT 94.10: Talk
Thursday, April 3, 2014, 17:30–17:45, HSZ 204
DFT+DMFT study of epitaxially strained LaVO3 — •Gabriele Sclauzero, Krzysztof Dymkowski, and Claude Ederer — Materials Theory, ETH Zurich, Switzerland
LaVO3 is a t2g perovskite showing a rich phase diagram as a function of temperature, with a paramagnetic Mott-Hubbard insulating state at room temperature. Recently, it has become possible to produce and characterize strained lattices of LaVO3 in thin films and superlattices of high structural quality. In such heterostructures both interface effects and epitaxial strain play an important role in the electronic reconstruction of the material, and it is often difficult to distinguish between these two effects in experiments. Moreover, the epitaxial strain can induce at least two different important modifications of the atomic geometry, namely: (i) a change in the amplitudes of the VO6 octahedral rotations; (ii) a stretching or compression of V–O bonds.
In this work, we perform density functional theory plus dynamical mean field theory (DFT+DMFT) simulations to study how the correlated Mott-Hubbard phase of LaVO3 is affected by epitaxial strain. We separate the effect of bond-length changes from that of octahedral rotations by comparing an idealized structure without rotations and a realistic one derived from the bulk orthorhombic phase. We interpret our findings through the strain-induced changes in the energies of the crystal-field t2g levels of the local DFT Hamiltonian and in the occupation matrix obtained from DMFT. A comparison with the t2g perovskite LaTiO3, which shows an insulator-to-metal transition upon compressive strain, will also be presented.