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arXiv 1007.3502cond-mat.str-el
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拓扑绝缘体中的相互作用效应和量子相变

Interaction effects and quantum phase transitions in topological insulators

Christopher N. Varney, Kai Sun, Marcos Rigol, Victor Galitski

摘要:

我们利用Lanczos算法研究了拓扑绝缘体中的强关联效应,并利用该算法精确计算了多粒子基态波函数及其拓扑性质.我们分析了一个简单的,非相互作用的Halfton模型的蜂窝晶格与已知的拓扑性质,并证明这些属性已经很明显,在小集群。接下来,我们考虑相互作用的费米子通过引入排斥最近邻相互作用。利用保真度度规和电荷密度波结构因子,在有限的相互作用强度下,发现了拓扑带绝缘体和拓扑平凡Mott绝缘相之间的一阶量子相变.我们构建了相图在$T = 0$作为一个功能的相互作用强度和复杂的相位为次近邻跳跃。最后,我们考虑了具有相互作用的硬核玻色子的Halfton模型,其中没有观察到拓扑相的证据。我们的工作的一个重要的一般结论是,尽管拓扑相位的内在非局部性,但它们的关键拓扑性质已经在小系统中表现出来,因此可以通过精确对角化进行数值研究并通过实验观察,例如,在光晶格中捕获离子和冷原子。

英文摘要:

We study strong correlation effects in topological insulators via the Lanczos algorithm, which we utilize to calculate the exact many-particle ground-state wave function and its topological properties. We analyze the simple, noninteracting Haldane model on a honeycomb lattice with known topological properties and demonstrate that these properties are already evident in small clusters. Next, we consider interacting fermions by introducing repulsive nearest-neighbor interactions. A first-order quantum phase transition was discovered at finite interaction strength between the topological band insulator and a topologically trivial Mott insulating phase by use of the fidelity metric and the charge-density-wave structure factor. We construct the phase diagram at $T = 0$ as a function of the interaction strength and the complex phase for the next-nearest-neighbor hoppings. Finally, we consider the Haldane model with interacting hard-core bosons, where no evidence for a topological phase is observed. An important general conclusion of our work is that despite the intrinsic nonlocality of topological phases their key topological properties manifest themselves already in small systems and therefore can be studied numerically via exact diagonalization and observed experimentally, e.g., with trapped ions and cold atoms in optical lattices.

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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