A coupled spin-electron model on a decorated square lattice formed by interconnected trigonal bipyramids is exactly solved by imposing two mobile electrons per each triangular plaquette with the help of a generalized decoration-iteration transformation, which establishes a precise mapping correspondence with the effective Ising model on a square lattice with temperature-dependent interaction. The investigated spin-electron model exhibits two different macroscopically degenerate ground states. The residual entropy of the first ground state, which shows a spontaneous ferromagnetic or ferrimagnetic long-range order depending on character of the exchange coupling, arises from chiral degrees of freedom of the mobile electrons. In contrast, the second ground state is disordered due to a kinetically driven frustration of the localized Ising spins triggered by the hopping term of the mobile electrons. The outstanding reentrant phase transitions connected with temperature induced formation of the spontaneous ferromagnetic or ferrimagnetic order can be found if the spin-electron model is driven sufficiently close to the ground-state phase boundary, but the disordered frustrated phase is the respective ground state. It is verified that the bipartite fermionic entanglement between two mobile electrons within the spontaneously ordered ferromagnetic or ferrimagnetic phase predominantly comes from their charge degrees of freedom, while the one within the disordered frustrated phase comes from both charge and spin degrees of freedom of these particles.

中文翻译：

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由三角双锥体组成的装饰方形晶格上耦合自旋电子模型的自发磁序以及自旋和电荷纠缠

在由互连三角双锥体形成的装饰方形晶格上的耦合自旋电子模型通过在广义装饰迭代变换的帮助下对每个三角形块施加两个移动电子来精确求解，这与有效的 Ising 模型建立了精确的映射对应关系在具有温度依赖性相互作用的方形晶格上。研究的自旋电子模型表现出两种不同的宏观简并基态。第一基态的残余熵，根据交换耦合的特征显示自发的铁磁或亚铁磁长程有序，由移动电子的手性自由度引起。相比之下，由于由移动电子的跳跃项触发的局部伊辛自旋的动力学驱动挫折，第二基态是无序的。如果将自旋电子模型驱动得足够接近基态相边界，则可以找到与温度诱导形成的自发铁磁或亚铁磁有序相关的突出重入相变，但无序受抑相是各自的基态。经验证，自发有序铁磁或亚铁磁相内两个移动电子之间的二分费米子纠缠主要来自它们的电荷自由度，而无序受挫相内的一个来自这些粒子的电荷和自旋自由度。