DC Josephson transport in a three-terminal Yu-Shiba-Rusinov system

Abstract

Scanning tunneling microscopy (STM) of magnetic adatoms on superconducting surfaces has established Yu-Shiba-Rusinov (YSR) states as a versatile platform for studying magnetic-superconducting interactions and phase-coherent quantum transport. Here, we investigate nonreciprocal supercurrent transport in a three-terminal Josephson junction comprising three BCS superconductors (`A', `B' and `C'), each coupled to a magnetic impurity hosting a pair of YSR states. Treating terminals `A' and `C' as primary transport electrodes and terminal `B' as a phase-control node, we demonstrate field-tunable nonreciprocal supercurrent between the primary electrodes. This effect requires both: the control terminal and broken particle-hole symmetry at least in one impurity attached to a primary electrode. Without the control terminal we show that the supercurrent remains reciprocal. Our results establish multi-terminal YSR junctions as a promising platform for engineering nonreciprocal superconducting transport and symmetry-breaking phenomena at the atomic scale.