  The effect of epitaxial strain on the structural and electronic properties of
LaVO_3 is investigated through density functional theory (DFT) and dynamical
mean field theory (DMFT). Two different growth orientations of the crystal are
considered, one preserving the bulk Pbnm space-group symmetry and another
giving rise to a symmetry lowering to P2_1/m. In the nonmagnetic DFT
structures, the two growth orientations are equally favored for all tensile
strains considered here, as well as for compressive strains weaker than -3%.
For stronger compressive strains, the P2_1/m orientation is favored and shows a
complete suppression of octahedral tilts along the out-of-plane direction.
Magnetically-ordered structures do not show a complete tilt suppression, but
the trend points to a similar reduction of the out-of-plane V-O-V bond angles
under compressive strain. Our DMFT calculations show that, in accord with
room-temperature experiments, the bulk paramagnetic Mott-insulating state of
LaVO_3 is robust against epitaxial strains attainable in thin films, since the
suppression of orbital fluctuations counteracts the effect of bandwidth
increase with compressive strain. Under stronger compressive strains, the
straightening of the V-O-V bonds in the P2_1/m geometry interferes with the
suppression of orbital fluctuations and hence perturbs the Mott phase more
strongly, albeit not enough to achieve a metallic phase.
