Kane-Mele Hubbard model on a zigzag ribbon: stability of the topological edge states and quantum phase transitions

Abstract

We study the quantum phases and phase transitions of the Kane-Mele Hubbard (KMH) model on a zigzag ribbon of honeycomb lattice at a finite size via the weak-coupling renormalization group (RG) approach. In the non-interacting limit, the KM model is known to support topological edge states where electrons show helical property with orientations of the spin and momentum being locked. The effective inter-edge hopping terms are generated due to finite-size effect. In the presence of an on-site Coulomb repulsive interaction and the inter-edge hoppings, special focus is put on the stability of the topological edge states (TI phase) in the KMH model against (i) the charge and spin gaped (II) phase, (ii) the charge gaped but spin gapless (IC) phase and (iii) the spin gaped but charge gapless (CI) phase depending on the number (even/odd) of the zigzag ribbons, doping level (electron filling factor) and the ratio of the Coulomb interaction to the inter-edge tunneling. We discuss different phase diagrams for even and odd numbers of zigzag ribbons. We find the TI-CI, II-IC, and II-CI quantum phase transitions are of the Kosterlitz-Thouless (KT) type. By computing various correlation functions, we further analyze the nature and leading instabilities of these phases.

14 pages, 17 figures

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Cited by in corpus (7)

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• Real-space analysis of Hatsugai-Kohmoto interaction
• Tight-Binding Device Modeling of 2-D Topological Insulator Field-Effect Transistors With Gate-Induced Phase Transition
• Topological multiferroic phases in the extended Kane-Mele-Hubbard Model in the Hofstadter regime
• Non-centrosymmetric superconductors on honeycomb lattice
• Fate of gapless edge states in two-dimensional topological insulators with Hatsugai-Kohmoto interaction
• Interplay between edge states and charge density wave order in the Falicov-Kimball model on a Haldane ribbon