Kavli Affiliate: Michael Wimmer
| First 5 Authors: Chun-Xiao Liu, Guanzhong Wang, Tom Dvir, Michael Wimmer,
| Summary:
The mesoscopic system of two separate quantum dots connected by a common
superconductor has been studied extensively for Cooper pair splitting, and is
predicted to be the building block of an emulated Kitaev chain. The physical
mechanisms underlying these phenomena include crossed Andreev reflection (CAR)
and elastic co-tunneling (ECT) between quantum dots. In this work, we consider
subgap Andreev bound states in a semiconductor-superconductor nanowire for
mediating interdot couplings. We find that the strengths of CAR and ECT have a
sensitive but different dependence on the physical parameters of the Andreev
bound states, e.g., chemical potential, spin-orbit coupling and Zeeman spin
splitting. Thus, the strengths as well as the ratio of CAR and ECT become
highly tunable by controlling an external gate or by varying an externally
applied magnetic field. In addition, unlike coupling through a metallic
superconductor, the interdot couplings no longer decay exponentially with the
dot distance. We also propose how to extract the strengths of CAR and ECT
experimentally. Our findings will be useful to maximizing the efficiency of
Cooper pair splitting as well as to implementing an emulated Kitaev chain at
the sweet spot.
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