Interaction-driven first-order and higher-order topological superconductivity

Fuente: arXiv
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Autori principali: Bonetti, Pietro M., Chakraborty, Debmalya, Wu, Xianxin, Schnyder, Andreas P.
Natura: Preprint
Pubblicazione: 2023
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author Bonetti, Pietro M.
Chakraborty, Debmalya
Wu, Xianxin
Schnyder, Andreas P.
author_facet Bonetti, Pietro M.
Chakraborty, Debmalya
Wu, Xianxin
Schnyder, Andreas P.
contents We investigate topological superconductivity in the Rashba-Hubbard model, describing heavy-atom superlattice and van der Waals materials with broken inversion. We focus in particular on fillings close to the van Hove singularities, where a large density of states enhances the superconducting transition temperature. To determine the topology of the superconducting gaps and to analyze the stability of their surface states in the presence of disorder and residual interactions, we employ an fRG+MFT approach, which combines the unbiased functional renormalization group (fRG) with a real-space mean-field theory (MFT). Our approach uncovers a cascade of topological superconducting states, including $A_1$ and $B_1$ pairings, whose wave functions are of dominant $p$- and $d$-wave character, respectively, as well as a time-reversal breaking $A_1 + i B_1$ pairing. While the $A_1$ and $B_1$ states have first order topology with helical and flat-band Majorana edge states, respectively, the $A_1 + i B_1$ pairing exhibits second-order topology with Majorana corner modes. We investigate the disorder stability of the bulk superconducting states, analyze interaction-induced instabilites of the edge states, and discuss implications for experimental systems.
format Preprint
id arxiv_https___arxiv_org_abs_2304_07100
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Interaction-driven first-order and higher-order topological superconductivity
Bonetti, Pietro M.
Chakraborty, Debmalya
Wu, Xianxin
Schnyder, Andreas P.
Superconductivity
Strongly Correlated Electrons
We investigate topological superconductivity in the Rashba-Hubbard model, describing heavy-atom superlattice and van der Waals materials with broken inversion. We focus in particular on fillings close to the van Hove singularities, where a large density of states enhances the superconducting transition temperature. To determine the topology of the superconducting gaps and to analyze the stability of their surface states in the presence of disorder and residual interactions, we employ an fRG+MFT approach, which combines the unbiased functional renormalization group (fRG) with a real-space mean-field theory (MFT). Our approach uncovers a cascade of topological superconducting states, including $A_1$ and $B_1$ pairings, whose wave functions are of dominant $p$- and $d$-wave character, respectively, as well as a time-reversal breaking $A_1 + i B_1$ pairing. While the $A_1$ and $B_1$ states have first order topology with helical and flat-band Majorana edge states, respectively, the $A_1 + i B_1$ pairing exhibits second-order topology with Majorana corner modes. We investigate the disorder stability of the bulk superconducting states, analyze interaction-induced instabilites of the edge states, and discuss implications for experimental systems.
title Interaction-driven first-order and higher-order topological superconductivity
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2304.07100