Non-local electron transport and cross-resistance peak in NSN heterostructures

TL;DR

This paper presents a microscopic theory explaining the temperature-dependent peak in non-local resistance of NSN heterostructures, highlighting the interplay of quasiparticle imbalance and Andreev processes, with results matching recent experiments.

Contribution

The study introduces a detailed microscopic model for non-local resistance peaks in NSN devices, emphasizing the power law dependence on superconductor thickness and explaining experimental observations.

Findings

Peak height and shape follow a power law with superconductor thickness.

Zero-temperature non-local resistance decays exponentially with thickness.

The theory aligns with recent experimental data.

Abstract

We develop a microscopic theory describing the peak in the temperature dependence of the non-local resistance of three-terminal NSN devices. This peak emerges at sufficiently high temperatures as a result of a competition between quasiparticle/charge imbalance and subgap (Andreev) contributions to the conductance matrix. Both the height and the shape of this peak demonstrate the power law dependence on the superconductor thickness $L$ in contrast to the zero-temperature non-local resistance which decays (roughly) exponentially with increasing $L$. A similar behavior was observed in recent experiments.