Conductance measurements cannot distinguish crossed Andreev reflection from elastic co-tunnelling in normal–superconductor–normal junctions

Nature Physics. 2026. P. 1198–1199.

Khrapai V., Tikhonov E.

Feng et al.1 presented transport measurements of three-terminal normal–superconductor–normal devices based on topological insulator nanowires. They measured the full differential conductance matrix, defined as Gij = ∂Ii /∂Vj , beyond the linear response regime as a function of various control parameters. Here i, j∈ [1, 2] denote normal terminals biased by the voltages V1 and V2 with respect to the grounded superconducting terminal, and I1 and I2 are the measured currents. The core idea is based on the assumption that a relative contribution of the two competing processes of crossed Andreev reflection (CAR) and elastic co-tunnelling (ECT) to non-local conductance can be systematically tuned by the choice of a bias voltage combination.

Keywords: Shot noise, дробовой шум, topological insulators, топологические изоляторы, полупроводниковые нанопровода, гибридные структуры со сверхпроводником, дробовой шум