Fabry-P & eacute;rot interference in Josephson junctions

Conductance of metallic heterostructures can be controlled by applying a gate voltage to a region in the transport channel. For sufficiently long phase coherent channels, oscillations appear in conductance versus chemical potential plot, which can be explained by Fabry-Perot interference. In this work, we study DC Josephson effect in a superconductor-normal metal-superconductor junctions. The chemical potential of the normal metal (NM) region can be tuned by an applied gate voltage. We numerically obtain the Andreev bound states formed within the superconducting gap and calculate Josephson current by summing up the currents carried by the occupied Andreev bound states. We find that the Josephson current oscillates as a function of the chemical potential in the NM region, and these oscillations can be explained by Fabry-Perot interference condition. We find that Josephson current carried by one bound state can be higher than that carried by two or more bound states.

Automated summary

The conductance of metallic heterostructures can be controlled by a gate voltage, leading to oscillations in the conductance versus chemical potential plot. This can be explained by Fabry-Perot interference. In this study, we investigate the DC Josephson effect in superconductor-normal metal-superconductor junctions, where the chemical potential in the normal metal region can be tuned by a gate voltage. Numerical calculations reveal the presence of Andreev bound states within the superconducting gap, and the Josephson current oscillates as a function of the chemical potential, consistent with Fabry-Perot interference. Furthermore, the Josephson current carried by one bound state may be higher than that carried by two or more bound states.