Observing the Berry phase in diffusive conductors: Necessary conditions for adiabaticity

TL;DR

This paper clarifies the conditions under which the Berry phase influences magnetoconductance in diffusive conductors, correcting recent claims that questioned its observability within the adiabatic regime.

Contribution

It demonstrates that the Berry phase effect is observable in the adiabatic regime, countering recent claims that the adiabatic approximation fails in this regime.

Findings

Berry phase affects magnetoconductance in diffusive conductors.

Adiabatic approximation remains valid in the identified regime.

Field-induced dephasing can obscure phase effects under certain conditions.

Abstract

In a recent preprint (cond-mat/9803170), van~Langen, Knops, Paasschens and Beenakker attempt to re-analyze the proposal of Loss, Schoeller and Goldbart (LSG) [Phys. Rev. B~48, 15218 (1993)] concerning Berry phase effects in the magnetoconductance of diffusive systems. Van Langen et al. claim that the adiabatic approximation for the Cooperon previously derived by LSG is not valid in the adiabatic regime identified by LSG. It is shown that the claim of van~Langen et al. is not correct, and that, on the contrary, the magnetoconductance does exhibit the Berry phase effect within the LSG regime of adiabaticity. The conclusion reached by van~Langen et al. is based on a misinterpretation of field-induced dephasing effects, which can mask the Berry phase (and any other phase coherent phenomena) for certain parameter values.