Light bipolarons stabilized by strong Peierls electron-vibration coupling: A new hope for high-temperature superconductivity [Justin Jankanas Doctoral Dissertation Award]

Striking emergent phenomena crucial to understanding the dynamical behavior of complex many-body molecular systems manifest thanks to coupling to vibrational excitations, including vibrationally stabilized Rydberg molecules and vibration-mediated binding of electron pairs in superconductors. Here, I show that the Peierls coupling, describing the modulation of electron motion due to vibrations, stabilizes light yet strongly bound bipolarons that survive strong Coulomb repulsion. I show that these properties result from the specific form of the vibration-mediated interaction, which is of 'pair-hopping' instead of regular density-density type. Furthermore, I provide evidence suggestive of a regime of bipolaronic phases stable against phase separation. These light bipolarons could well undergo Bose-Einstein condensation at high temperatures, opening a door to a new mechanism for high-temperature superconductivity. This may help resolve open questions regarding superconductivity in vibrationally coupled systems.