NONUNIVERSAL CRITICAL-BEHAVIOR AND 1ST-ORDER TRANSITIONS IN A COUPLED XY-ISING MODEL | |
Article | |
关键词: SPACE RENORMALIZATION-GROUP; PHASE-TRANSITIONS; MONTE-CARLO; TRIANGULAR LATTICE; COULOMB-GAS; JUNCTION ARRAYS; MAGNETIC-FIELD; CRITICAL-POINT; CENTRAL CHARGE; COMPLEX ZEROS; | |
DOI : 10.1103/PhysRevB.44.4819 | |
来源: SCIE |
【 摘 要 】
We study, by a Migdal-Kadanoff approximation and Monte Carlo simulations, the phase diagram of a two-dimensional coupled XY-Ising model. This model can describe phase transitions in different systems with underlying continuous and Z2 symmetries. Depending on the parameters, we find separate XY, Ising and first-order transitions. Also, a line of continuous transitions is found with simultaneous loss of XY and Ising order and varying critical exponents. The fully frustrated XY and Josephson-junction systems can be considered to lie along different paths in the model which can result in nonuniversal behavior if the transition is a single one.
【 授权许可】
Free