English

Voltage controllable superconducting state in the multi-terminal superconductor-normal metal bridge

Superconductivity 2021-05-26 v1

Abstract

We study voltage controllable superconducting state in multi-terminal bridge composed of the dirty superconductor/pure normal metal (SN) bilayer and pure normal metal. In the proposed system small control current IctrlI_{ctrl} flows via normal bridge, creates voltage drop VV and modifies distribution function of electrons in connected SN bilayer. In case of long normal bridge the voltage induced nonequilibrium effects could be interpreted in terms of increased local electron temperature. In this limit we experimentally find large sensitivity of critical curent IcI_c of Cu/MoN/Pt-Cu bridge to IctrlI_{ctrl} and relatively large current gain which originate from steep dependence of IcI_c on temperature and large IcI_c (comparable with theoretical depairing current of superconducting bridge). In the short normal bridge deviation from equilibrium cannot be described by simple increase of local temperature but we also theoretically find large sensitivity of IcI_c to control current/voltage. In this limit we predict existence at finite VV of so called in-plane Fulde-Ferrell state with spontaneous currents in SN bilayer. We argue that its appearance is connected with voltage induced paramagnetic response in N layer.

Keywords

Cite

@article{arxiv.2105.06780,
  title  = {Voltage controllable superconducting state in the multi-terminal superconductor-normal metal bridge},
  author = {M. Yu. Levichev and I. Yu. Pashenkin and N. S. Gusev and D. Yu. Vodolazov},
  journal= {arXiv preprint arXiv:2105.06780},
  year   = {2021}
}

Comments

8 pages, 5 figures