Nature of the high-pressure transition in Fe2O3 hematite.
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.
Badro
James
J
Laboratoire de Minéralogie-Cristallographie de Paris (UMR 7590), CNRS Case 115, 4 Place Jussieu, 75252 Paris CEDEX 05, France.
Fiquet
Guillaume
G
Struzhkin
Viktor V
VV
Somayazulu
Maddury
M
Mao
Ho-kwang
HK
Shen
Guoyin
G
Le Bihan
Tristan
T