Chiral superconductivity near a fractional Chern insulator

Fuente: arXiv
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Autori principali: Wang, Taige, Zaletel, Michael P.
Natura: Preprint
Pubblicazione: 2025
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author Wang, Taige
Zaletel, Michael P.
author_facet Wang, Taige
Zaletel, Michael P.
contents Superconductivity arising from fully spin-polarized, repulsively interacting electrons can host intrinsically chiral Cooper pairs and Majorana zero modes, yet no concrete microscopic route to such a state has been established. Motivated by recent observations in twisted homobilayer MoTe$_2$ and rhombohedral pentalayer graphene, where fractional Chern insulators (FCIs) appear adjacent to spin-valley-polarized superconductors, we investigate a minimal model: spinless electrons in the lowest Landau level subject to a tunable periodic potential. Large-scale density-matrix renormalization group (DMRG) calculations reveal that, as the FCI gap closes, two nearly degenerate phases emerge before the system turns metallic: a chiral $f$-wave superconductor and a $\sqrt{3} \times \sqrt{3}$ charge-density wave (CDW) whose energies differ by less than $1\%$. These two competing states mirror the superconducting and re-entrant integer quantum Hall (RIQH) phases observed experimentally near the FCI regime. The superconducting dome survives realistic Coulomb interaction, light doping, and various lattice geometry. Melting the FCI therefore provides a new mechanism for realizing spin-polarized chiral superconductivity and RIQH order. We predict that twisted MoTe$_2$ at larger twist angles will develop a superconducting dome even at filling $ν= 2/3$, and suppressing this superconductivity with a magnetic field should drive the system into an RIQH state.
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id arxiv_https___arxiv_org_abs_2507_07921
institution arXiv
publishDate 2025
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spellingShingle Chiral superconductivity near a fractional Chern insulator
Wang, Taige
Zaletel, Michael P.
Strongly Correlated Electrons
Superconductivity
Superconductivity arising from fully spin-polarized, repulsively interacting electrons can host intrinsically chiral Cooper pairs and Majorana zero modes, yet no concrete microscopic route to such a state has been established. Motivated by recent observations in twisted homobilayer MoTe$_2$ and rhombohedral pentalayer graphene, where fractional Chern insulators (FCIs) appear adjacent to spin-valley-polarized superconductors, we investigate a minimal model: spinless electrons in the lowest Landau level subject to a tunable periodic potential. Large-scale density-matrix renormalization group (DMRG) calculations reveal that, as the FCI gap closes, two nearly degenerate phases emerge before the system turns metallic: a chiral $f$-wave superconductor and a $\sqrt{3} \times \sqrt{3}$ charge-density wave (CDW) whose energies differ by less than $1\%$. These two competing states mirror the superconducting and re-entrant integer quantum Hall (RIQH) phases observed experimentally near the FCI regime. The superconducting dome survives realistic Coulomb interaction, light doping, and various lattice geometry. Melting the FCI therefore provides a new mechanism for realizing spin-polarized chiral superconductivity and RIQH order. We predict that twisted MoTe$_2$ at larger twist angles will develop a superconducting dome even at filling $ν= 2/3$, and suppressing this superconductivity with a magnetic field should drive the system into an RIQH state.
title Chiral superconductivity near a fractional Chern insulator
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2507.07921