title: Fluctuating lattice constants of indium under high pressure.
abstract: Recent high-pressure investigations of elemental In have yielded controversial results. We show that the observed high-pressure face-centered orthorhombic (fco) structure can be explained as an intermediate state between two body-centered tetragonal (bct) structures with different c/a ratios (c/a < square root [2] and c/a > square root [2], respectively). In a pressure range from about 50 to 200 GPa these two bct structures correspond to local minima of the total energy with respect to orthorhombic distortion of the ground-state bct In structure. The fco saddle point represents a tiny barrier and even at low temperatures rapid structural fluctuations should occur. Such a situation has not been identified in any other elemental metal.
authors.affiliation: Department of Inorganic Chemistry, Stockholm University, S-106 91 Stockholm, Sweden.
authors.forename: A S
authors.initials: AS
authors.lastname: Mikhaylushkin
authors.forename: U
authors.initials: U
authors.lastname: Häussermann
authors.forename: B
authors.initials: B
authors.lastname: Johansson
authors.forename: S I
authors.initials: SI
authors.lastname: Simak