Sublattice modulated superconductivity in the kagome Hubbard model
Tilman Schwemmer, Hendrik Hohmann, Matteo Dürrnagel, Janik Potten, Jacob Beyer, Stephan Rachel, Yi‐Ming Wu, S. Raghu, Tobias Müller, Werner Hanke, Ronny Thomale
Abstract
We identify a superconducting order featuring spatial pair modulations on the kagome lattice subject to on-site Hubbard $U$ and nearest-neighbor $V$ interactions. Within our functional renormalization group analysis, this state appears with a concomitant $d$-wave superconducting (SC) instability at zero lattice momentum, where it distinguishes itself through intra-unit-cell modulations of the pairing function thus breaking the discrete space group symmetry. The relative weight of the sublattice modulated superconductor (SMS) and $d$-wave SC is influenced by the absolute interaction strength and coupling ratio $V/U$. Parametrically adjacent to this domain at weak coupling, we find an intra-unit-cell modulated vestigial charge density wave and an $s$-wave SC instability. Our study provides a microscopic setting and thorough description of this novel SMS arising within a translation symmetry broken background.