Quantum Oscillations in Nodal Line Systems

TL;DR

This paper investigates magnetic quantum oscillations in three-dimensional nodal line semimetals, revealing topological Fermi surface features and Berry phase signatures through analysis of Landau levels and extremal orbits.

Contribution

It identifies the topological nature of Fermi surfaces and distinguishes different Hamiltonian classes with identical Fermi geometries in nodal line semimetals.

Findings

Detection of non-trivial $$ Berry phase in extremal orbits.

Identification of Fermi surface topology with genus one and electron-hole pockets.

Analysis of Landau levels corresponding to different magnetic field orientations.

Abstract

We study signatures of magnetic quantum oscillations in three-dimensional nodal line semimetals at zero temperature. The extended nature of the degenerate bands can result in a Fermi surface geometry with topological genus one, as well as a Fermi surface of electron and hole pockets encapsulating the nodal line. Moreover, the underlying two-band model to describe a nodal line is not unique, in that there are two classes of Hamiltonian with distinct band topology giving rise to the same Fermi surface geometry. After identifying the extremal cyclotron orbits in various magnetic field directions, we study their concomitant Landau levels and resulting quantum oscillation signatures. By Landau-fan-diagram analyses we extract the non-trivial $\pi$ Berry phase signature for extremal orbits linking the nodal line.