1. Thermal first-order phase transitions, Ising critical points, and reentrance in the Ising-Heisenberg model on the diamond-decorated square lattice in a magnetic field
- Author
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Jozef Strečka, Katarína Karl'ová, Taras Verkholyak, Nils Caci, Stefan Wessel, Andreas Honecker, and Honecker, Andreas
- Subjects
Condensed Matter - Strongly Correlated Electrons ,[PHYS.COND.CM-SM] Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech] ,Statistical Mechanics (cond-mat.stat-mech) ,Strongly Correlated Electrons (cond-mat.str-el) ,[PHYS.COND.CM-SCE] Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el] ,FOS: Physical sciences ,Condensed Matter - Statistical Mechanics - Abstract
The thermal phase transitions of a spin-1/2 Ising-Heisenberg model on the diamond-decorated square lattice in a magnetic field are investigated using a decoration-iteration transformation and classical Monte Carlo simulations. A generalized decoration-iteration transformation maps this model exactly onto an effective classical Ising model on the square lattice with temperature-dependent effective nearest-neighbor interactions and magnetic field strength. The effective field vanishes along a ground-state phase boundary of the original model, separating a ferrimagnetic and a quantum monomer-dimer phase. At finite temperatures this phase boundary gives rise to an exactly solvable surface of discontinuous (first-order) phase transitions, which terminates in a line of Ising critical points. The existence of discontinuous reentrant phase transitions within a narrow parameter regime is reported and explained in terms of the low-energy excitations from both phases. These exact results, obtained from the mapping to the zero-field effective Ising model are corroborated by classical Monte Carlo simulations of the effective model., Comment: 17 pages, 15 figures
- Published
- 2023