Phase diagram of the interacting Haldane model with spin-dependent sublattice potentials

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Hauptverfasser: Shao, Can, Luo, Hong-Gang
Format: Preprint
Veröffentlicht: 2024
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author Shao, Can
Luo, Hong-Gang
author_facet Shao, Can
Luo, Hong-Gang
contents Using the exact-diagonalization (ED) and mean-field (MF) approaches, we investigate the ground-state phase diagram of the interacting Haldane model on the honeycomb lattice, incorporating spin-dependent sublattice potentials $Δ_{σ,α}$. Here $α=\text{A}$,$\text{B}$ and $σ=\uparrow$,$\downarrow$ denote the sublattice and spin components, respectively. Setting $Δ_{σ,\text{A}}=+Δ$ ($-Δ$) and $Δ_{σ,\text{B}}$$=-Δ$ ($+Δ$) for $σ=\uparrow$ ($\downarrow$) results in the system favoring a spin ordered state. Conversely, introducing the nearest-neighbor Coulomb interaction can induce charge ordering in the system. Due to the competition between these factors, we observe that in both ED and MF approaches, an exotic state with Chern number $C=1$ survives amidst two locally ordered phases and a topologically ordered phase with $C=2$. In the ED method, various properties, such as the fidelity metric, the excitation gap and the structure factors, are employed to identify critical points. In the MF method, using a sufficiently large lattice size, we define the local order parameters and band gaps to characterize the phase transitions. The interacting Haldane model and the spin-dependent lattice potential may be experimentally realized in an ultracold atom gas, providing a potential means to detect this intriguing state.
format Preprint
id arxiv_https___arxiv_org_abs_2401_17813
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Phase diagram of the interacting Haldane model with spin-dependent sublattice potentials
Shao, Can
Luo, Hong-Gang
Strongly Correlated Electrons
Quantum Gases
Using the exact-diagonalization (ED) and mean-field (MF) approaches, we investigate the ground-state phase diagram of the interacting Haldane model on the honeycomb lattice, incorporating spin-dependent sublattice potentials $Δ_{σ,α}$. Here $α=\text{A}$,$\text{B}$ and $σ=\uparrow$,$\downarrow$ denote the sublattice and spin components, respectively. Setting $Δ_{σ,\text{A}}=+Δ$ ($-Δ$) and $Δ_{σ,\text{B}}$$=-Δ$ ($+Δ$) for $σ=\uparrow$ ($\downarrow$) results in the system favoring a spin ordered state. Conversely, introducing the nearest-neighbor Coulomb interaction can induce charge ordering in the system. Due to the competition between these factors, we observe that in both ED and MF approaches, an exotic state with Chern number $C=1$ survives amidst two locally ordered phases and a topologically ordered phase with $C=2$. In the ED method, various properties, such as the fidelity metric, the excitation gap and the structure factors, are employed to identify critical points. In the MF method, using a sufficiently large lattice size, we define the local order parameters and band gaps to characterize the phase transitions. The interacting Haldane model and the spin-dependent lattice potential may be experimentally realized in an ultracold atom gas, providing a potential means to detect this intriguing state.
title Phase diagram of the interacting Haldane model with spin-dependent sublattice potentials
topic Strongly Correlated Electrons
Quantum Gases
url https://arxiv.org/abs/2401.17813