Seminar – Maria N. Gastiasoro

On Wednesday 18th November at 11:30 AM. we have the pleasure of welcoming Maria N. Gastiasoro (DIPC, Spain) for a seminar in the TRT auditorium.

Title:

Dynamical Rashba Coupling and Unconventional Superconductivity in Quantum Paraelectrics

Abstract:

Doped SrTiO₃ becomes superconducting at extremely low carrier densities, where the Fermi energy is smaller than the relevant phonon energies. This places it outside the standard BCS and Migdal–Eliashberg paradigm. Its sister compound KTaO₃ adds a twist: superconductivity appears at interfaces, with critical temperatures that depend strongly on crystal orientation and critical fields far beyond the Pauli limit. The pairing mechanism in these quantum paraelectrics is still debated.

A natural candidate is the soft polar mode, a lattice vibration whose simplest coupling to the electrons is, however, forbidden by symmetry. In this talk I will give an overview of our work on a dynamical Rashba-like coupling to this mode, enabled by spin–orbit coupling, and discuss its implications for superconductivity in both materials. I will then present recent results on the microscopic origin of this coupling, and close with some of the many questions that remain open.