Campus Units

Ames Laboratory, Chemistry, Materials Science and Engineering

Document Type

Article

Publication Version

Published Version

Publication Date

2004

Journal or Book Title

Physical Review B

Volume

69

Issue

144102

First Page

1

Last Page

13

DOI

10.1103/PhysRevB.69.144102

Abstract

Temperature-dependent single crystal x-ray-diffraction studies revealed a reversible first-order phase transition in Er5Si4. The high-temperature phase adopts the orthorhombic Gd5Si4-type structure, and the low-temperature phase has the monoclinic Gd5Si2Ge2-type structure. Unlike the magnetic/martensitic transition in Gd5Si2Ge2, the structural change in Er5Si4 is not coupled with a magnetic transition, and the structural sequence below room temperature is just the reverse. A vibrational mode that breaks half of the interslab silicon dimers and rotates slabs in the monoclinic structure, thus lowering the symmetry from Pnma to P1121/a, has been identified using Landau theory. While the monoclinic phase is electronically stabilized at low temperatures, the orthorhombic phase is entropically preferable at high temperatures.

Comments

This article is from Physical Review B 69 (2004): 1, doi:10.1103/PhysRevB.69.144102. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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