Regular Article

Generation of Terahertz oscillations by thin superconducting film in fluctuation regime

¹ Department of Theoretical Physics, Faculty of Physics, St. Clement of Ohrid University at Sofia, 5 James Bourchier Blvd., 1164 Sofia, Bulgaria
² LIONS, NIMBE, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif sur Yvette Cedex, France
³ CNR-SPIN, Viale del Politecnico 1, 00133 Rome, Italy

^a e-mail: mishonov@gmail.com

Received: 29 January 2019
Received in final form: 28 May 2019
Published online: 17 July 2019

Abstract

Explicit analytical expressions for conductivity of a superconducting film above and below critical temperature in an arbitrary electric field are derived in the frameworks of the time dependent Ginzburg-Landau theory. It is confirmed that slightly below critical temperature the differential conductivity of superconducting film can become negative for small enough values of electric field. This fact may cause generation of electromagnetic oscillations if the superconducting film is appropriately coupled of with a resonator. Their maximal frequency is proportional to the value of critical temperature of superconducting transition. The obtained results can stimulate the development of Terahertz generators on the basis of high temperature superconducting films.