Phase transition and thermodynamics of quantum XY model in two dimensions
- Materials Simulation Center, Beckman Institute, California Institute of Technology, Pasadena, California 91125 (United States)
The two-dimensional spin-1/2 {ital XY} model is investigated via an extensive quantum Monte Carlo simulation on square lattices as large as 128{times}128. The transverse susceptibility and correlation length show precise thermodynamic scaling behaviors of a phase transition of the Kosterlitz-Thouless type at {ital kT}{sub {ital c}}/{ital J}=0.353(3). The correlation functions near the transition point exhibit a universal scaling behavior. Various critical exponents are determined and our results demonstrate that the universality class of the two-dimensional quantum system with continuous symmetry is the same as its classical analog. The specific heat exhibits a finite peak around {ital kT}/{ital J}=0.45, decreases very rapidly near {ital T}{sub {ital c}}, and falls off as {ital T}{sup 2} near {ital T}=0, validating the spin-wave treatment. The ground-state energy is {minus}0.5543(1){ital J} per spin.
- OSTI ID:
- 5105040
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 45:1; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
PHASE TRANSFORMATIONS
CRYSTAL MODELS
CORRELATION FUNCTIONS
GROUND STATES
KOSTERLITZ-THOULESS THEORY
MAGNETIC SUSCEPTIBILITY
MONTE CARLO METHOD
SCALING
SPECIFIC HEAT
ENERGY LEVELS
FUNCTIONS
MAGNETIC PROPERTIES
MATHEMATICAL MODELS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
665000* - Physics of Condensed Matter- (1992-)