Electric field effect on epitaxial YBa₂Cu₃O_7−x thin films

By applying a strong electric field perpendicular to the surface of an ultrathin, highly uniform epitaxial YBa2Cu3O7¿x film, the critical current was depressed and enhanced over 20% at temperatures close to Tc, and 5% at lower temperatures. Careful analysis of the electric field dependent I-V characteristics and Arrhenius plots indicate that the electric field effect can be interpreted as a change in the pinning potential and/or the vortex-antivortex interaction potential in the Kosterlitz-Thouless regime, as a result of a change in the carrier density in the superconductor.