Interpretation of the angular dependence of the de Haas-van Alphen effect in MgB_2

TL;DR

This study investigates the angular dependence of the de Haas-van Alphen effect in MgB_2, revealing that amplitude dips are due to frequency beats rather than spin-zero effects, indicating small Stoner enhancement factors.

Contribution

The paper clarifies the origin of amplitude dips in MgB_2's dHvA signals, challenging previous assumptions and providing detailed analysis of the Fermi surface behavior.

Findings

Dip in dHvA amplitude caused by frequency beat, not spin-zero effect

Small Stoner enhancement factors in MgB_2

Angular dependence of dHvA signals elucidated

Abstract

We present detailed results for the amplitude and field dependence of the de Haas-van Alphen (dHvA) signal arising from the electron-like $\pi$ sheet of Fermi surface in MgB_2. Our data and analysis show that the dip in dHvA amplitude when the field is close to the basal plane is caused by a beat between two very similar dHvA frequencies and not a spin-zero effect as previously assumed. Our results imply that the Stoner enhancement factors in MgB_2 are small on both the Sigma and Pi sheets.