Recent developments in the determination of the amplitude and phase of quantum oscillations for the linear chain of coupled orbits

TL;DR

This paper investigates the amplitude and phase of quantum oscillations in quasi-two-dimensional organic metals with a linear chain of coupled orbits, highlighting the importance of second order effects and field-dependent phases beyond the Lifshits-Kosevich model.

Contribution

It introduces an analysis of second order damping factors and field-dependent phase effects in quantum oscillations for complex Fermi surface topologies.

Findings

Second order terms significantly affect Fourier component amplitudes at high fields and low temperatures.

Damping factors depend on magnetic breakdown field, effective masses, and Landé factors.

Field-dependent Onsager phase factors influence oscillation spectra.

Abstract

De Haas-van Alphen oscillations are studied for Fermi surfaces (FS) illustrating the model proposed by Pippard in the early sixties, namely the linear chain of orbits coupled by magnetic breakdown. This FS topology is relevant for many multiband quasi-two dimensional (q-2D) organic metals such as $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ and $\theta$-(BEDT-TTF)$_4$CoBr$_4$(C$_6$H$_4$Cl$_2$) which are considered in detail. Whereas the Lifshits-Kosevich model only involves a first order development of field- and temperature-dependent damping factors, second order terms may have significant contribution on the Fourier components amplitude for such q-2D systems at high magnetic field and low temperature. The strength of these second order terms depends on the relative value of the involved damping factors, which are in turns strongly dependent on parameters such as the magnetic breakdown field, effective masses and, most of all, effective Land\'{e} factors. In addition, the influence of field-dependent Onsager phase factors on the oscillation spectra is considered.