arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1008.2183cond-mat.str-el
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三角格点上扩展的Falicov-Kimball模型

An extended Falicov-Kimball model on a triangular lattice

Umesh K. Yadav, T. Maitra, Ishwar Singh, A. Taraphder

摘要:

电子中的阻挫和关联的综合效应是近来人们相当感兴趣的一个问题。在这种情况下,Falicov-Kimball模型上的三角形晶格与两个本地化的状态,相关的某些相关的系统,被认为是。利用该模型的局域对称性,我们的数值研究揭示了一些轨道有序的基态,通过参数的微小变化进行调谐,而局域态和扩展态之间的量子涨落产生均匀的混合价。这些有序态中的大多数破坏了哈密顿量的反演对称性,导致轨道驱动的铁电性。我们证明了当基态不均匀时,不存在自发对称性破缺。这项研究可能是相关的挫折系统,如$GdI_2$,$NaTiO_2$(在其低温C2/m相),其中两个莫特局域态耦合到导带。

英文摘要:

The combined effect of frustration and correlation in electrons is a matter of considerable interest of late. In this context a Falicov-Kimball model on a triangular lattice with two localized states, relevant for certain correlated systems, is considered. Making use of the local symmetries of the model, our numerical study reveals a number of orbital ordered ground states, tuned by the small changes in parameters while quantum fluctuations between the localized and extended states produce homogeneous mixed valence. The inversion symmetry of the Hamiltonian is broken by most of these ordered states leading to orbitally driven ferroelectricity. We demonstrate that there is no spontaneous symmetry breaking when the ground state is inhomogeneous. The study could be relevant for frustrated systems like $GdI_2$, $NaTiO_2$ (in its low temperature C2/m phase) where two Mott localized states couple to a conduction band.

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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