Correlations in Novel Quantum Materials 2023 (CNQM2023)

van Hove, Rashba, and Hubbard meet to form first-order and higher-order topological superconductors

24 Jul 2023, 16:45

2h 45m

2D5 (MPI-FKF)

Contributed Poster Poster Session

Speaker

Pietro Maria Bonetti (MSFK)

Description

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 develop 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 states, respectively, the $A_1+i{B}_1$ pairing exhibits second-order topology with Majorana corner modes.