Pressure-induced volume collapse and structural phase transitions in SrRuO3

We report on the low temperature (6 K) structural properties of SrRuO3 under quasi-hydrostatic pressure studied by synchrotron X-ray powder diffraction in a diamond anvil cell. First principle calculations predict a first-order perovskite (N) to post-perovskite (pPv) phase transition at similar to 40 GPa accompanied by a 1.9% volume collapse. Our results rule out the occurrence of a pPv phase to 54 GPa. Instead, we find a Pv to monoclinic to triclinic sequence of phase transitions. The monoclinic to triclinic phase transition at similar to 38 GPa is accompanied by a 3.5% volume collapse. X-ray absorption spectroscopy indicates that this volume collapse is not accompanied by a change in Ru valence state. Our results should help guide improvements to theoretical treatments of this and other correlated d-electron systems based on density functional theory. (c) 2013 Elsevier Inc. All rights reserved.