Collective excitations and universal broadening of cyclotron absorption in Dirac semimetals in a quantizing magnetic field

TL;DR

This paper investigates the electromagnetic collective excitations in Dirac semimetals under strong magnetic fields, revealing Landau damping regions, different collective modes, and universal broadening of cyclotron absorption, with implications for magneto-optical effects.

Contribution

It introduces a detailed analysis of collective excitations and broadening phenomena in Dirac semimetals in quantizing magnetic fields, highlighting universal features and potential observable effects.

Findings

Identification of Landau damping regions for electron transitions.

Discovery of different collective excitation modes near damping boundaries.

Prediction of universal broadening of cyclotron absorption with magnetic field variation.

Abstract

The spectrum of electromagnetic collective excitations in Dirac semimetals placed in a quantizing magnetic field is considered. We have found the Landau damping regions using the energy and momentum conservation law for allowed transitions between one-particle states of electron excitations. Analysis of dispersion equations for longitudinal and transverse waves near the window boundaries in the Landau damping regions reveals different types of collective excitations. We also indicate the features of universal broadening of cyclotron absorption for a magnetic field variation in systems with linear dispersion of the electron spectrum. The use of the obtained spectrum also allows us to predict a number of oscillation and resonance effects in the field of magneto-optical phenomena.