de Haas-van Alphen Oscillations in a Superconducting State at High Magnetic Fields

TL;DR

This paper demonstrates that de Haas-van Alphen oscillations persist in a superconductor at high magnetic fields due to a gapless quasiparticle spectrum, with results aligning well with experimental data on V3Si.

Contribution

It reveals the persistence of quantum oscillations in the superconducting state at high fields and quantifies the amplitude reduction due to gapless Fermi surface regions.

Findings

Quantum oscillations persist below the upper critical field.

Amplitude reduction factor is proportional to (max(T,Gamma)/delta)^2.

Good agreement with experimental data on V3Si.

Abstract

Low-temperature quantum oscillations of the dHvA amplitude are shown to persist far below the upper critical field of a strongly type-II superconductor, due to the gapless nature of the BCS quasiparticle spectrum in high fields. The dHvA amplitude in the superconducting state is smaller than its normal state countpart by factor ~[max(T,Gamma]/delta]**2, where Gamma is the damping. This factor reflects the presence of a small gapless portion of the fermi surface, surrounded by regions where the BCS gap is large. The agreement with recent experimental data on V3Si is very good.