| 1. |
- Bonetti, Pietro M., et al.
(författare)
-
Interaction-driven first-order and higher-order topological superconductivity
- 2024
-
Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 109:18
-
Tidskriftsartikel (refereegranskat)abstract
- 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 ?1 and ?1 pairings, whose wave functions are of dominant ?- and ?-wave character, respectively, as well as a time-reversal breaking ?1+??1 pairing. While the ?1 and ?1 states have first-order topology with helical and flat-band Majorana edge states, respectively, the ?1+??1 pairing exhibits second-order topology with Majorana corner modes. We investigate the disorder stability of the bulk superconducting states, analyze interaction-induced instabilities of the edge states, and discuss implications for experimental systems.
|
|
| 2. |
- Wu, Xianxin, et al.
(författare)
-
Crossover between electron-electron and electron-phonon mediated pairing on the kagome lattice
- 2024
-
Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 109:1
-
Tidskriftsartikel (refereegranskat)abstract
- We study electron-electron and electron-phonon mediated pairing in the Holstein extended Hubbard model on the kagome lattice near the van Hove fillings, and we investigate their combined effects on electron pairing states. We find that their combination can promote exotic pairings in a crossover region, where the filling is close to a van Hove singularity. In particular, at the p-type van Hove filling, the E1u (p-wave) and B2u(fy3-3yx2-wave) pairings become leading, and at the m-type van Hove filling, the E1u and A2g (i-wave) pairings get promoted. Moreover, we show that the electron-phonon interaction acquires a significant momentum dependence, due to the sublattice texture of the Fermi surfaces, which can promote non-s-wave pairing. We present a detailed analysis of these pairing propensities, and we discuss implications for the vanadium-based kagome superconductors AV3Sb5.
|
|
