Mott insulators in moiré transition metal dichalcogenides at fractional fillings: Slave-rotor mean-field theory

Fuente: arXiv
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Main Authors: Song, Zhenhao, Seifert, Urban F. P., Luo, Zhu-Xi, Balents, Leon
Format: Preprint
Published: 2023
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author Song, Zhenhao
Seifert, Urban F. P.
Luo, Zhu-Xi
Balents, Leon
author_facet Song, Zhenhao
Seifert, Urban F. P.
Luo, Zhu-Xi
Balents, Leon
contents In this work, we study a slave-rotor mean-field theory of an extended Hubbard model, applicable to transition metal dichalcogenide moiré systems, that captures both the formation of Wigner crystals as well as exotic spin states on top of these charge backgrounds. Phase diagrams are mapped out for different choices of long-range Coulomb repulsion strength, reproducing several experimentally found Wigner crystal states. Assuming unbroken time reversal symmetry, we find several spin liquid states as well as dimer states at fractional fillings. While spin dimer states are always found to have the lowest mean field energy, several spin liquid states are energetically competitive and may be stabilized by including gauge fluctuations or further interaction terms. We further discuss possible experimental signatures of these states pertinent to two-dimensional moiré heterostructures.
format Preprint
id arxiv_https___arxiv_org_abs_2307_05676
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Mott insulators in moiré transition metal dichalcogenides at fractional fillings: Slave-rotor mean-field theory
Song, Zhenhao
Seifert, Urban F. P.
Luo, Zhu-Xi
Balents, Leon
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
In this work, we study a slave-rotor mean-field theory of an extended Hubbard model, applicable to transition metal dichalcogenide moiré systems, that captures both the formation of Wigner crystals as well as exotic spin states on top of these charge backgrounds. Phase diagrams are mapped out for different choices of long-range Coulomb repulsion strength, reproducing several experimentally found Wigner crystal states. Assuming unbroken time reversal symmetry, we find several spin liquid states as well as dimer states at fractional fillings. While spin dimer states are always found to have the lowest mean field energy, several spin liquid states are energetically competitive and may be stabilized by including gauge fluctuations or further interaction terms. We further discuss possible experimental signatures of these states pertinent to two-dimensional moiré heterostructures.
title Mott insulators in moiré transition metal dichalcogenides at fractional fillings: Slave-rotor mean-field theory
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2307.05676