Phys.org June 20, 2024
When the electron-phonon coupling is quadratic in the phonon coordinates, electrons can pair to form bipolarons due to phonon zero-point fluctuations. A team of researchers in the US (Harvard University, Connecticut University, MIT) studied superconductivity originating from this pairing mechanism in a minimal model and revealed that, in the strong coupling regime, the critical temperature () was only mildly suppressed by the coupling strength, in stark contrast to the exponential suppression in linearly coupled systems, thus implied higher optimal values. They demonstrated that large coupling constants of this flavor were achieved in known materials such as perovskites, and discussed strategies to realize such superconductivity using superlattices… read more. TECHNICAL ARTICLE
Illustration of the phonon wave function amplitude before (in blue) and after (in red) a bipolaron hops from site 1 to site 2… Credit: Phys. Rev. Lett. 132, 226001, 31 May 2024