IISER MOHALI

Abstract: Topological superconductors have become an important research topic, stimulated by their potential for quantum and superconducting applications. Since the topology only protects against perturbations smaller than the superconducting gap, it is of paramount importance to find topological superconductors with large gaps and high transition temperatures. One possible path to high-temperature topological superconductivity is to consider materials where the Fermi level lies close to van Hove singularities (VHSs), which enhance the density of states. Motivated by this, in this talk, I will show the conditions under which topological superconductivity emerges close to van Hove fillings on the kagome [1] and square [2] lattices. For the kagome lattice we find that the different sublattice textures of the m-type and p-type VHSs influence the propensity for topological superconductivity. For both lattices our findings unravel a variety of different topological superconducting states with characteristic topological properties, including Majorana edge and corner modes. I will also discuss how van Hove singularities can act as generic platforms in the search for new topological quantum matter.

References:
[1] Xianxin Wu, Debmalya Chakraborty, Andreas P. Schnyder, and Andres Greco, Crossover between electron-electron and electron-phonon mediated pairing on the Kagome lattice, Phys. Rev. B 109, 014517 (2024).

[2] Pietro M. Bonetti*, Debmalya Chakraborty*, Xianxin Wu, and Andreas P. Schnyder, Interaction-driven first-order and higher-order topological superconductivity, Phys. Rev. B (Letters) 109, L180509 (2024). *=Equal contribution.