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We perform a systematic study of Andreev conversion at the interface between a superconductor and graphene in the quantum Hall (QH) regime. We find that the probability of Andreev conversion from electrons to holes follows an unexpected but clear trend: the dependencies on temperature and magnetic field are nearly decoupled. We discuss these trends and the role of the superconducting vortices, whose normal cores could both absorb and dephase the individual electrons in a QH edge. Our study may pave the road to engineering future generation of hybrid devices for exploiting superconductivity proximity in chiral channels. 

Superconducting diodes areproposed nonreciprocal circuit elements thatshould exhibit nondissipative transport inone direction while being resistive intheopposite direction. Multiple examples ofsuch devices have emerged inthepastcouple ofyears; however, their efficiency istypically limited, andmost ofthem require amagnetic field tofunction. Here wepresent adevice thatachieves efficiencies approaching 100% while operating atzero field. Our samples consist ofanetwork ofthree graphene Josephson junctions linked byacommon superconducting island, towhich werefer asa Josephson triode. Thethree-terminal nature ofthedevice inherently breaks theinversion symmetry, andthecontrol current applied toone ofthecontacts breaks thetime-reversal symmetry. Thetriode’s utility isdemonstrated byrectifying asmall (nA scale amplitude) applied square wave. Wespeculate thatdevices ofthistype could berealistically employed inthemodern quantum circuits.