Probing topology in thin films with quantum Sondheimer oscillations

TL;DR

This paper develops a quantum theory of Sondheimer oscillations in thin films, revealing how band topology influences oscillation frequency and enabling direct probing of Landau levels.

Contribution

It introduces a quantum framework showing how topological band properties modify Sondheimer oscillations in thin films, unlike traditional semiclassical understanding.

Findings

Quantum corrections alter SO frequency based on band topology.

Topological effects appear in SO frequency, not just phase.

The theory explains experimental spectra and damping mechanisms.

Abstract

Sondheimer oscillations (SO) are magnetoresistance oscillations occurring in thin films due to the commensurability between cyclotron motion and sample thickness, and are traditionally regarded as a purely semiclassical size effect. Here we develop a general quantum theory of SO for thin-film conductors in the quantum limit of a large magnetic field. We show that corrections arising from band topology modify the SO frequency, in contrast to Shubnikov-de Haas oscillations where topological information appears only in the phase. As a consequence, quantum SO provide a direct and robust probe of the full Landau level spectrum. Applying our framework to a minimal model with tunable Berry phase, we demonstrate how topology manifests itself in experimentally accessible magneto-oscillation spectra and discuss damping mechanisms including surface roughness.