Comment on "Anomalous proximity effect in underdoped YBa_2Cu_3O_{6+x} Josephson junctions"

TL;DR

This paper critically examines claims of an anomalously long-ranged proximity effect in underdoped YBCO, demonstrating that conventional theory can account for the observed long-range effects when experimental nuances are considered.

Contribution

It clarifies that the long-range proximity effect observed is not anomalous but consistent with existing theories when experimental specifics are included.

Findings

Conventional proximity effect theory explains long-range effects in YBCO.

Experimental details are crucial in interpreting proximity effect measurements.

The observed effects are not necessarily indicative of new physics.

Abstract

In recent photodoping experiments Decca et al. [PRL 85, 3708 (2000)] have observed an unusually long-ranged proximity effect between the superconducting and insulating phases of YBCO. Here we critically examine the claim in that reference that such long range is anomalous. We show that, once the novel nature of the experiments has been properly accounted for, the conventional theory of the proximity effect predicts comparably long ranges.