Han Zhaoyu, Kivelson Steven A, Volkov Pavel A
Department of Physics, Stanford University, Stanford, California 94305, USA.
Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA.
Phys Rev Lett. 2024 May 31;132(22):226001. doi: 10.1103/PhysRevLett.132.226001.
When the electron-phonon coupling is quadratic in the phonon coordinates, electrons can pair to form bipolarons due to phonon zero-point fluctuations, a purely quantum effect. We study superconductivity originating from this pairing mechanism in a minimal model and reveal that, in the strong coupling regime, the critical temperature (T_{c}) is only mildly suppressed by the coupling strength, in stark contrast to the exponential suppression in linearly coupled systems, thus implying higher optimal T_{c} values. We demonstrate that large coupling constants of this flavor are achieved in known materials such as perovskites, and discuss strategies to realize such superconductivity using superlattices.
