Thermoelectric Detection of Crossed Andreev Reflections in Quantum Hall/Superconductor Hybrid Structures

Hybrid structures combining quantum Hall edge states with superconductors provide a platform to study non-Abelian quasiparticles and Cooper pair splitting via crossed Andreev reflection (CAR). In CAR, electrons from upstream chiral edge modes of the superconductor are converted into holes injected into downstream modes. Most studies are focused on ohmic response of CAR, which lead to a negative downstream resistance. In this talk, we interface quantum Hall edge channels in cadmium arsenide (Cd₃As₂) films with a narrow NbN strip and measure the downstream electrical and thermoelectric responses. Both quantities exhibit magnetic-field-dependent oscillations. The ohmic response remains dominated by electron-like carriers, likely due to elastic tunneling, whereas the thermoelectric signal alternates in sign, indicating contributions from hole-like carriers generated by Andreev conversion. The results point to thermoelectric measurements as a promising probe for CAR and quantum entanglement.