title: Nature of the high-pressure transition in Fe2O3 hematite.
abstract: We present a new method to separate the crystallographic and electronic phase transitions in hematite using x-ray emission spectroscopy and x-ray diffraction. Our observations, based on the behavior of a metastable high-pressure phase in the stability domain of the low-pressure phase, show that the electronic transition is preempted by the crystallographic transition. The former occurs only afterwards in the high-pressure phase, possibly as a result of a Mott transition. The idea that the electronic transition drives the transition in hematite is therefore invalidated. Such methods should help elucidate the mechanics and the driving forces behind a number of first-order high-pressure phase transitions.
authors.affiliation: Laboratoire de Minéralogie-Cristallographie de Paris (UMR 7590), CNRS Case 115, 4 Place Jussieu, 75252 Paris CEDEX 05, France.
authors.forename: James
authors.initials: J
authors.lastname: Badro
authors.forename: Guillaume
authors.initials: G
authors.lastname: Fiquet
authors.forename: Viktor V
authors.initials: VV
authors.lastname: Struzhkin
authors.forename: Maddury
authors.initials: M
authors.lastname: Somayazulu
authors.forename: Ho-kwang
authors.initials: HK
authors.lastname: Mao
authors.forename: Guoyin
authors.initials: G
authors.lastname: Shen
authors.forename: Tristan
authors.initials: T
authors.lastname: Le Bihan