A THz time-domain susceptibility for superconductors including strong-current effects
Abstract
Finite-difference time-domain methods are increasingly being used to develop, model and analyze the response of materials, including engineered metamaterials that may contain superconductors. Though simple and useful expressions for the time-domain susceptibility exist for basic metals and dielectrics, the time-domain response for a superconductor has not been developed, mainly because the frequency-dependent expressions themselves are rather complex. In this paper we present a simple approximate expression for the time-domain susceptibility of a superconductor for the hbar/2Delta time scale (where Delta is the BCS energy gap) that fulfills causality requirements, and demonstrate its ability to model the transmission and reflection of a fully-gapped superconductor in the THz region. By allowing Delta to be a function of current, we also show how this model function can be used to describe nonlinear microwave response in superconductors.
Keywords
Cite
@article{arxiv.1307.5113,
title = {A THz time-domain susceptibility for superconductors including strong-current effects},
author = {Xiaoxiang Xi and G. L. Carr},
journal= {arXiv preprint arXiv:1307.5113},
year = {2013}
}