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arXiv 1910.09752cond-mat.str-el
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半填充装饰蜂窝晶格上的电荷密度波

Charge Density Waves on a Half-Filled Decorated Honeycomb Lattice

Chunhan Feng, Huaiming Guo, Richard T. Scalettar

摘要:

紧束缚模型,如哈伯德哈密顿量,最经常探讨的上下文中的均匀点间跳跃$t$。电子-电子相互作用,如果足够大的相比,这个不变性的$t$,可以引起有序的磁相和莫特绝缘体过渡,特别是在相称的填充。非均匀$t$的更复杂的情况已经在许多情况下进行了研究,也许最突出的是在多带几何结构中,其中在不同重叠程度的轨道之间存在跳跃的自然区别。在本文中,我们探讨了多个动能尺度和电子-声子相互作用的相互作用所产生的相关问题。具体来说,我们使用量子蒙特卡罗(DQMC)解决半填充的Holstein哈密顿的“装饰蜂窝晶格”,由六边形与内部跳跃$t$耦合在一起的$t^{\,\prime}$。这种跳跃的调制在狄拉克谱中引入了一个间隙,并影响了拓扑相位的性质。我们确定的范围内的$t/t^{\,\prime}$值支持电荷密度波(CDW)相位约狄拉克点的均匀跳跃$t=t^{\,\prime}$,以及临界转变温度$T_c$。将QMC模拟结果与平均场论(MFT)的结果进行了比较。

英文摘要:

Tight binding models like the Hubbard Hamiltonian are most often explored in the context of uniform intersite hopping $t$. The electron-electron interactions, if sufficiently large compared to this translationally invariant $t$, can give rise to ordered magnetic phases and Mott insulator transitions, especially at commensurate filling. The more complex situation of non-uniform $t$ has been studied within a number of situations, perhaps most prominently in multi-band geometries where there is a natural distinction of hopping between orbitals of different degree of overlap. In this paper we explore related questions arising from the interplay of multiple kinetic energy scales and electron-phonon interactions. Specifically, we use Determinant Quantum Monte Carlo (DQMC) to solve the half-filled Holstein Hamiltonian on a `decorated honeycomb lattice', consisting of hexagons with internal hopping $t$ coupled together by $t^{\,\prime}$. This modulation of the hopping introduces a gap in the Dirac spectrum and affects the nature of the topological phases. We determine the range of $t/t^{\,\prime}$ values which support a charge density wave (CDW) phase about the Dirac point of uniform hopping $t=t^{\,\prime}$, as well as the critical transition temperature $T_c$. The QMC simulations are compared with the results of Mean Field Theory (MFT).

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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