arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.04193cond-mat.str-el
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半填充平带Kagome电子系统的量子相位

Quantum Phases of Kagome Electron System with Half-Filled Flat Bands

Yafei Ren, Hong-Chen Jiang, Zhenhua Qiao, D. N. Sheng

摘要:

研究了最低平带半满的kagome晶格上自旋费米子的量子相图。为了理解磁性、平带阻挫和排斥相互作用之间的竞争,我们采用了一个扩展的$t$ - $J$模型,其中考虑了跳跃能$t$、反铁磁海森堡相互作用$J$和短程邻近Hubbard相互作用$V$。在弱$J$体系中,我们发现了一个完全自旋极化的相,这进一步支持了由短程排斥相互作用驱动的自发Chern绝缘相。这个阶段仍然出现在平面铁磁性,而非相互作用的陈绝缘体消失的对称性约束。随着$J$逐渐增加,铁磁性被抑制,并且系统首先变为具有大磁化强度的部分极化,然后进入具有表现出消失的磁化强度的基态的非极化相。我们确定这一非极化相作为绝缘体与一个负电荷密度波。最后,我们讨论了我们的理论发现的潜在的实验观察。

英文摘要:

We study the quantum phase diagram of spinful fermions on kagome lattice with half-filled lowest flat bands. To understand the competition between magnetism, flat band frustration, and repulsive interactions, we adopt an extended $t$-$J$ model, where the hopping energy $t$, antiferromagnetic Heisenberg interaction $J$, and short-range neighboring Hubbard interaction $V$ are considered. In the weak $J$ regime, we identify a fully spin-polarized phase, which can further support the spontaneous Chern insulating phase driven by the short-range repulsive interaction. This phase still emerges with in-plane ferromagnetism, whereas the non-interacting Chern insulator disappears constrained by symmetry. As $J$ gradually increases, the ferromagnetism is suppressed and the system first becomes partially-polarized with large magnetization and then enters a non-polarized phase with the ground state exhibiting vanishing magnetization. We identify this non-polarized phase as an insulator with a nematic charge density wave. In the end, we discuss the potential experimental observations of our theoretical findings.

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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