Publications

We use a Ginzburg-Landau approach to show that a suitably strong electric field can drive a phase transition from a superconductor to a normal metal. The transition is induced by taking into account corrections to the permittivity due to the superconductive gap and persists even when screening effects are considered. We test the model against recent experimental observations in which a strong electric field has been observed to control the supercurrent in superconducting thin films. We find excellent agreement with the experimental data and are able to explain several observed features. We additionally suggest a way to test our theoretical proposal via superconductor-superconductor electron tunneling.

A static electric field has traditionally been thought to play little role in ideal conductors because screening by mobile carriers prevents it from penetrating deep into a metal. Recent experiments, however, indicate that static electric fields can manipulate the superconductive properties of metallic BCS thin films and weaken the critical current. This contribution discusses possible explanations for this effect using the analogy between superconductivity and quantum electrodynamics noted by Nambu and Jona-Lasinio.

A deep connection has long linked superconductivity and quantum field theory, notably through the Anderson-Higgs mechanism and similarities between Dirac and Bogoliubov-de Gennes equations. We extend this parallel and predict a superconducting Schwinger effect: an electrostatic field can generate two coherent excitations from the superconducting ground-state condensate. Unlike dissipative thermal excitations, these form a macroscopically coherent and dissipationless state. We discuss how the superconducting state is weakened by these excitations and how the effect could be tested experimentally, illuminating the interaction between superconductors and electric fields.