On the de Haas - van Alphen oscillations in quasi-two-dimensional metals: effect of the Fermi surface curvature

TL;DR

This paper provides a theoretical analysis of how the Fermi surface curvature affects de Haas-van Alphen oscillations in quasi-two-dimensional metals, revealing conditions for pronounced effects and explaining experimental observations.

Contribution

It demonstrates that zero curvature at extremal cross-sections significantly alters oscillation shape and amplitude, and analyzes angular dependencies related to Fermi surface geometry.

Findings

Zero curvature at extremal cross-sections enhances oscillation effects.

A peak in oscillation amplitude appears at small tilt angles of magnetic field.

Results explain experimental peaks observed in organic metals.

Abstract

Here, we present the results of theoretical analysis of the de Haas-van Alphen oscillations in quasi-two-dimensional normal metals. We had been studying effects of the Fermi surface (FS) shape on these oscillations. It was shown that the effects could be revealed and well pronounced when the FS curvature becomes zero at cross-sections with extremal cross-sectional areas. In this case both shape and amplitude of the oscillations could be significantly changed. Also, we analyze the effect of the FS local geometry on the angular dependencies of the oscillation amplitudes when the magnetic field is tilted away from the FS symmetry axis by the angle $\theta.$ We show that a peak appears at $\theta \approx 0$ whose height could be of the same order as the maximum at the Yamaji angle. This peak emerges when the FS includes zero curvature cross-sections of extremal areas. Such maximum was observed in experiments on the $\alpha-(BETS)_4TIHg(SeCN)_4.$ The obtained results could be applied to organic metals and other quasi-two-dimensional compounds.