论文标题
延长的nagaoka铁磁性的有限温度特性
Finite-temperature properties of extended Nagaoka ferromagnetism
论文作者
论文摘要
我们研究了哈伯德模型的有限温度特性，其中包括粒子浴的位点，该位点被提议作为微观模型，以在有限的电子密度下显示流动的铁磁性。我们使用直接的数值方法，例如精确的对角和随机矢量方法。数量的温度依赖性在温度的整个范围内进行了调查。我们发现特定的热量具有多个峰，这对应于不同能量尺度的订购过程。特别是，磁顺序出现在非常低的温度下。根据粒子浴和库仑相互作用的化学潜力，该系统表现出摩托菌绝缘子的巡回铁磁状态或抗铁磁状态。从显微镜上看，这两种类型的订单之间的竞争会导致局部自旋相关性的特殊订购过程。发现一些局部铁磁相关性是鲁棒的，这表明铁磁相关性源于短期群集中巡回电子的运动。
We study finite-temperature properties of a Hubbard model including sites of a particle bath which was proposed as a microscopic model to show itinerant ferromagnetism at finite electron density. We use direct numerical methods, such as exact diagonalization and random vector methods. The temperature dependence of quantities is surveyed in the full range of the temperature. We find that the specific heat has several peaks, which correspond to ordering processes in different energy scales. In particular, magnetic order appears at very low temperature. Depending on the chemical potential of the particle bath and the Coulomb interaction, the system exhibits an itinerant ferromagnetic state or an antiferromagnetic state of the Mott insulator. Microscopically the competition between these two types of orderings causes a peculiar ordering process of local spin correlations. Some local ferromagnetic correlations are found to be robust, which indicates that the ferromagnetic correlation originates from the motion of itinerant electrons in a short-range cluster.
