• Rapid Communication

Magnetic-order-driven topological transition in the Haldane-Hubbard model

Wei Zheng, Huitao Shen, Zhong Wang, and Hui Zhai
Phys. Rev. B 91, 161107(R) – Published 23 April 2015
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Abstract

In this Rapid Communication we study the Haldane model with on-site repulsive interactions at half-filling. We show that the mean-field Hamiltonian with magnetic order effectively modifies parameters in the Haldane Hamiltonian, such as sublattice energy difference and phase in next-nearest hopping. As interaction increases, increasing of magnetic order corresponds to varying these parameters and, consequently, drives topological transitions. At the mean-field level, one scenario is that the magnetic order continuously increases, and, inevitably, the fermion gap closes at the topological transition point. Beyond the mean field, fluctuation-induced interaction can further open up the gap, rendering a first-order transition. Another scenario is a first-order transition at the mean-field level across which a canted magnetic order develops discontinuously, avoiding the fermion gap closing. We find that both scenarios exist in the phase diagram of the Haldane-Hubbard model. Our predication is relevant to recent experimental realization of the Haldane model in cold-atom system.

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  • Received 18 January 2015

DOI:https://doi.org/10.1103/PhysRevB.91.161107

©2015 American Physical Society

Authors & Affiliations

Wei Zheng, Huitao Shen, Zhong Wang*, and Hui Zhai

  • Institute for Advanced Study, Tsinghua University, Beijing 100084, China

  • *wangzhongemail@gmail.com
  • hzhai@mail.tsinghua.edu.cn

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Issue

Vol. 91, Iss. 16 — 15 April 2015

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