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arXiv 0912.4155cond-mat.str-elcond-mat.stat-mech
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外磁场中Falicov-Kimball模型的轨道效应

The Falicov-Kimball model in external magnetic field: orbital effects

Maciej Wrobel, Marcin Mierzejewski, Maciej M. Maska

摘要:

研究了二维Falicov-Kimball模型在垂直于晶格方向的外部磁场作用下的热力学性质。在跳跃项中,通过Peierls替换考虑了该场。在非相互作用的情况下,依赖于场的能谱形成了著名的霍夫施塔特蝴蝶。结果表明,对于任意非零相互作用强度和任意磁场,在足够低的温度下,能谱中存在一个能隙。当耦合较弱时,能隙随温度的升高而消失,当耦合较强时,能隙在高温下仍存在。数值结果已获得的Monte Carlo技术的基础上修改的Metropolis算法的帮助。

英文摘要:

We study thermodynamic properties of the two-dimensional (2D) Falicov-Kimball model in the presence of external magnetic field perpendicular to the lattice. The field is taken into account by the Peierls substitution in the hopping term. In the non-interacting case the field dependent energy spectrum forms the famous Hofstadter butterfly. Our results indicate that for arbitrary nonzero interaction strength and arbitrary magnetic field there is a gap in the energy spectrum at sufficiently low temperature. The gap vanishes with increase of temperature for weak coupling, however, it persists at high temperatures if the coupling is strong enough. Numerical results have been obtained with the help of Monte Carlo technique based on a modified Metropolis algorithm.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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