Comparative study of the superconductivity in the Holstein and optical Su-Schrieffer-Heeger models

Abstract

Su-Schrieffer-Heeger (SSH) electron-phonon ($e\ensuremath{-}p\phantom{\rule{0}{0ex}}h$) interactions have been theorized to play critical roles in several novel states of matter, ranging from nontrivial topological states to high-temperature bipolaronic superconductivity. This work compares the superconducting and competing charge and bond correlations of the two-dimensional Holstein and optical (SSH) models. The authors find that near half-filling, light SSH (bi)polarons support superconductivity to larger values of $e\ensuremath{-}p\phantom{\rule{0}{0ex}}h$ coupling compared to the Holstein polaron. These results are essential for identifying and engineering bipolaronic superconductivity in quantum materials.