Cooper-pair splitting in two parallel InAs nanowires

Abstract

We report on the fabrication and electrical characterization of an InAs double-nanowire (NW) device consisting of two closely placed parallel NWs coupled to a common superconducting electrode on one side and individual normal metal leads on the other. In this new type of device we detect Cooper-pair splitting (CPS) with a sizeable efficiency of correlated currents in both NWs. In contrast to earlier experiments, where CPS was realized in a single NW, demonstrating an intrawire electron pairing mediated by the superconductor (SC), our experiment demonstrates an interwire interaction mediated by the common SC. The latter is the key for the realization of zero-magnetic field Majorana bound states, or Parafermions; in NWs and therefore constitutes a milestone towards topological superconductivity. In addition, we observe transport resonances that occur only in the superconducting state, which we tentatively attribute to Andreev bound states and/or Yu-Shiba resonances that form in the proximitized section of one NW.

Strong electron-electron interactions of a Tomonaga-Luttinger liquid observed in InAs quantum wires

“…They rely on high-efficient Cooper pair splitting into the two quantum wires, which arises due to strong e-e interactions. We note that efficient Cooper pair splitting [15,16] and a transparent interface with a superconductor has been recently demonstrated in self-assembled InAs nanowires [17,18] and quantum well [19]. With this outlook, providing wires with both strong e-e interactions and strong SOIs seems beneficial.…”

Majorana Kramers Pairs in Higher-Order Topological Insulators

“…As a consequence, the MKPs proposed in this work are robust against TRS-preserving disorder. It is also worth pointing out that, in addition to the MKPs, our setup can work as a Cooper pair splitter-a source of spatially separated spin-entangled electron pairs [106][107][108][109][110][111][112][113][114][115][116][117][118]. Finally, we remark that detection of MKPs with the parity-controlled 2π Josephson effect, which gives distinct signatures from unpaired MBSs [119], and braiding-based [120,121] or measurement-based [122] quantum computation schemes utilizing MKPs have been widely discussed in the literature.…”

Spontaneous Josephson π junctions with topological superconductors

“…Experimentally, these transitions should be observable when one avoids fixing the phase externally (for instance using a flux loop), but rather let the phase be determined based on energetic considerations. In particular, if the TRITOPSs in the junction are re-alized by a semiconductor-superconductor heterostructure [16,28,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53], it is important to avoid direct coupling between the parent superconductors, as this can give rise to a Josephson coupling that competes with the mechanism studied above.…”