https://doi.org/10.1140/epjb/e2016-70528-1
Regular Article
BCS theory of driven superconductivity
1 Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg, Germany
2 I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstr. 9, 20355 Hamburg, Germany
3 The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
a
e-mail: michael.thorwart@physik.uni-hamburg.de
Received: 9 September 2016
Published online: 9 November 2016
We study the impact of a time-dependent external driving of the lattice phonons in a minimal model of a BCS superconductor. Upon evaluating the driving-induced vertex corrections of the phonon-mediated electron-electron interaction, we show that parametric phonon driving can be used to elevate the critical temperature Tc, while a dipolar phonon drive has no effect. We provide simple analytic expressions for the enhancement factor of Tc. Furthermore, a mean-field analysis of a nonlinear phonon-phonon interaction also shows that phonon anharmonicities further amplify Tc. Our results hold universally for the large class of normal BCS superconductors.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2016