Applications of the transfer integral techniques to two-dimensional lattices

R.A. GUYER; PABLO SERRA; CARLOS A. CONDAT; CARLOS E. BUDDE

PHYSICA A - STATISTICAL AND THEORETICAL PHYSICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1986 vol. 136 p. 370 - 392

0378-4371

The transfer integral formalism is used to study the statistical mechanical properties of atwo-component field defined on a two-dimensional lattice. This field, taken to have anisotropicelasticity, is subject to both a nonlinear local potential and an external field. The free energy andmagnetization are calculated using an approximate solution of the transfer integral problem. Thissolution employs a strong-coupling approximation to the transfer integral equation and a variationalprinciple with correlated Gaussian trial functions. As a special case, the 4? model for a structuralphase transition, in the absence of an applied field, is analyzed; a phase diagram consistent withprevious calculations is obtained. The phase diagram for a two-component field, with anisotropicelasticity, a 44 local potential, and an external field, is also considered.