Tunable $t-t'-U$ Hubbard models in twisted square homobilayers

Fuente: arXiv
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Autori principali: Eugenio, P. Myles, Luo, Zhu-Xi, Vishwanath, Ashvin, Volkov, Pavel A.
Natura: Preprint
Pubblicazione: 2024
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author Eugenio, P. Myles
Luo, Zhu-Xi
Vishwanath, Ashvin
Volkov, Pavel A.
author_facet Eugenio, P. Myles
Luo, Zhu-Xi
Vishwanath, Ashvin
Volkov, Pavel A.
contents Square lattice Hubbard models with tunable hopping ratio $t'/t$ are highly promising for realizing a variety of quantum phases and for shedding light on key puzzles in correlated quantum materials, including higher-temperature superconductivity. We show that twisted square lattice homo-bilayers generically offer such tunability when the flat bands originate from the corner of the Brillouin zone. We reveal an emergent symmetry at low twist-angles, absent in single layers, that necessitates the vanishing of nearest neighbor hopping ($t=0$). This symmetry can be lifted by an inter-layer displacement field or by an in-plane magnetic field, introducing tunable $t$ and anisotropy, allowing access to a wide range of $t'/t$ ratios for correlated electrons on a moiré square lattice.
format Preprint
id arxiv_https___arxiv_org_abs_2406_02448
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Tunable $t-t'-U$ Hubbard models in twisted square homobilayers
Eugenio, P. Myles
Luo, Zhu-Xi
Vishwanath, Ashvin
Volkov, Pavel A.
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Square lattice Hubbard models with tunable hopping ratio $t'/t$ are highly promising for realizing a variety of quantum phases and for shedding light on key puzzles in correlated quantum materials, including higher-temperature superconductivity. We show that twisted square lattice homo-bilayers generically offer such tunability when the flat bands originate from the corner of the Brillouin zone. We reveal an emergent symmetry at low twist-angles, absent in single layers, that necessitates the vanishing of nearest neighbor hopping ($t=0$). This symmetry can be lifted by an inter-layer displacement field or by an in-plane magnetic field, introducing tunable $t$ and anisotropy, allowing access to a wide range of $t'/t$ ratios for correlated electrons on a moiré square lattice.
title Tunable $t-t'-U$ Hubbard models in twisted square homobilayers
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2406.02448