Comment on "Long-range crossed Andreev reflection in a topological insulator nanowire proximitized by a superconductor" by Junya Feng et al

TL;DR

This paper critically analyzes a recent experiment on crossed Andreev reflection in a topological insulator nanowire, arguing that the interpretation is misleading due to bias voltage effects and incomplete conductance data.

Contribution

It provides a critical perspective on the interpretation of experimental results, emphasizing the importance of bias effects and comprehensive conductance measurements.

Findings

Bias voltages impact conductance randomly, not systematically.

Bias symmetry can be explained by self-gating effects.

Full conductance matrix knowledge is insufficient to determine dominant processes.

Abstract

We argue that the interpretation of the experiment [Nature Physics 21, 708-715 (2025)] is misleading in two respects. First, the bias voltages impact the non-local differential conductance randomly, rather than systematically, and the bias symmetry of the non-local conductance in Fig. 3 can be explained by a fine tuned self-gating effect. Second, the full knowledge of the conductance matrix is insufficient to conclude on the relative values of the crossed-Andreev and elastic cotunneling probabilities, in particular on the dominance of one of them.