Year: 2026
Type: preprint
Abstract: Crossed Andreev reflection (CAR) is a nonlocal quantum transport phenomenon that arises at the interfaces between a superconductor and two spatially separated metals. In this process, an electron incident from one metal combines with another electron originating from the other metal to form a Cooper pair in the SC. In this work, we theoretically investigate the quantum transport properties of a device comprising a central $s$-wave superconductor sandwiched between two bipolar magnetic semiconductor (BMS) leads. BMS materials possess a unique bandstructure where the conduction and valence bands are fully spin-polarized in opposite directions. By applying independent gate voltages to the two BMS leads, we selectively tune their chemical potentials to configure an antiparallel spin alignment at the Fermi energy. In the absence of spin-orbit coupling (SOC), this specific configuration perfectly suppresses both local Andreev reflection and direct electron tunneling (ET), thereby isolating and profoundly enhancing CAR. The introduction of Rashba SOC, however, induces spin-flip scattering that relaxes these strict selection constraints, yielding finite probabilities for competing scattering channels and subsequently reducing the overall CAR efficiency. Nevertheless, for SOC strengths below a critical threshold, CAR remains the dominant transport mechanism over ET. This proposed architecture provides a scalable, stray-field-free method to achieve purely electrostatic control over nonlocal transport, advancing the development of highly efficient superconducting spintronic devices.
Source: arXiv (Cornell University)
Authors: Naveen, Polireddi, Soori, Abhiram
Institution: University of Hyderabad
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Award: G3181870834
OpenAlex ID: W7161548441