# Quantum oscillations in Dirac magnetoplasmons

## TL;DR

This paper reveals that in three-dimensional Dirac semimetals, magnetoplasmon frequencies exhibit quantum oscillations in a magnetic field, providing a new way to probe many-body effects beyond classical plasmon behavior.

## Contribution

It demonstrates that magnetoplasmon frequencies in Dirac semimetals show quantum oscillations, unlike in traditional electron gases, using the random phase approximation.

## Key findings

- Magnetoplasmon dispersion shows quantum oscillations in magnetic fields.
- Loss function varies with propagation direction relative to magnetic field.
- Transition from high to low magnetic field regimes discussed.

## Abstract

The plasmon frequency in standard electron gases with a parabolic single-particle dispersion is a purely classical quantity that is not sensitive to electron interactions or the equation of state. We demonstrate that this canonical result no longer holds for plasmons in three-dimensional semimetals, which can thus be used to probe many-body effects in these systems. In particular, we show that the plasmon frequency in an external magnetic field displays quantum oscillations, which is not the case for the electron gas. Using the random phase approximation, results are presented for the magnetoplasmon dispersion and the loss function in Dirac semimetals. We include a full discussion of the loss function in a magnetic field as a function of the direction of propagation with respect to the magnetic field direction and discuss the transition from large magnetic fields to the low-field limit.