论文标题
在磁场上的钻石装饰的正方形晶格上的伊森 - 海森贝格模型中的热一阶相变，伊斯丁的临界点和重新进入
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
论文作者
论文摘要
使用装饰识别转换和经典的蒙特卡洛模拟研究了磁场上的Spin-1/2 Ising-Heisenberg模型的热相变。广义的装饰 - 识别转换将该模型精确地映射到具有温度依赖性有效的最近邻邻相互作用和磁场强度的正方形晶格上的有效经典ising模型。有效场沿原始模型的地面相边界消失，将铁磁性和量子单体二聚体相分开。在有限温度下，该相边界产生了不连续（一阶）相变的确切解决的表面，该表面终止于Ising临界点。在狭窄的参数状态下存在不连续的恢复相变的存在，并根据两个阶段的低能量激励进行了解释。这些确切的结果，从映射到零视野有效模型获得的结果得到了有效模型的经典蒙特卡洛模拟的证实。
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.
