Interaction-driven topological insulators on the kagome and the decorated honeycomb lattices
Interaction-driven topological insulators on the kagome and the decorated honeycomb lattices
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DOI：
10.1103/physrevb.82.075125
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发表时间：
2010-05
影响因子：
3.7
通讯作者：
J. Wen;A. Ruegg;C.C.-Joseph Wang;G. Fiete
中科院分区：
文献类型：
--
作者：
J. Wen;A. Ruegg;C.C.-Joseph Wang;G. Fiete
本文研究了kagome和装饰蜂窝（星星）晶格上具有排斥作用的无自旋和有自旋扩展Hubbard模型。利用Hartree-Fock平均场理论，我们证明了在实验上合理的参数范围内，存在具有非平凡拓扑不变量（Chern数或${Z}_{2}$不变量）的相互作用驱动的绝缘相.这些阶段发生在填充分数，涉及狄拉克点或二次带交叉点的非相互作用的限制。我们提出了全面的平均场相图，这些晶格和讨论之间的竞争拓扑非平凡的阶段和许多其他有序状态，包括各种电荷，自旋和键序。我们的研究结果表明，拓扑绝缘体${Z}_{2}$应该存在于一些几乎没有或没有内禀自旋-轨道耦合的系统中。
We study the spinless and spinful extended Hubbard models with repulsive interactions on the kagome and the decorated honeycomb (star) lattice. Using Hartree-Fock mean-field theory, we show that interaction-driven insulating phases with nontrivial topological invariants (Chern number or ${Z}_{2}$ invariant) exist for an experimentally reasonable range of parameters. These phases occur at filling fractions which involve either Dirac points or quadratic band crossing points in the noninteracting limit. We present comprehensive mean-field phase diagrams for these lattices and discuss the competition between topologically nontrivial phases and numerous other ordered states, including various charge, spin, and bond orderings. Our results suggest that ${Z}_{2}$ topological insulators should be found in a number of systems with either little or no intrinsic spin-orbit coupling.