Phase diagram of the Frenkel-Kontorova-Devonshire model

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.7981· OSTI ID:7198368

Little, S; Zangwill, A ^[1]

---

1. School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

We study a generalization of the Frenkel-Kontorova (FK) model where the usual harmonic spring potential between neighboring atoms is replaced by a phenomenological potential identical in form to a sixth-degree Landau free-energy functional proposed by Devonshire. The resulting model is a natural extension of current FK-type models with nonconvex interactions. It also provides a first step toward the construction of a theory of the structure of an epitaxial film that undergoes a first-order phase transition from a high-symmetry phase to a degenerate low-symmetry phase. The phase diagram is obtained as a function of temperature and misfit (for representative choices of the remaining parameters) by use of the effective potential method of Griffiths and Chou. Among other unusual features, we find commensurate phases and soliton structures in which all competing phases are present simultaneously.

• DOE Contract Number: FG05-88ER45369
• OSTI ID: 7198368
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:13; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

665000* -- Physics of Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTAL-PHASE TRANSFORMATIONS
DIAGRAMS
ENERGY
EPITAXY
FREE ENERGY
LAYERS
ONE-DIMENSIONAL CALCULATIONS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES