Plasmon signature in Dirac-Weyl liquids

TL;DR

This paper theoretically investigates the temperature-dependent plasmon modes in three-dimensional Dirac liquids, revealing a tunable, superlinear temperature dependence and a fundamental many-body effect manifested as a logarithmic correction, serving as an experimental signature.

Contribution

It introduces a comprehensive theoretical analysis of finite-temperature plasmons in 3D Dirac liquids, highlighting universal behavior and many-body effects unique to relativistic Dirac materials.

Findings

Intrinsic plasmons exist only at finite temperature with superlinear dependence.

Doped systems show a temperature-dependent minimum in plasmon dispersion.

Logarithmic renormalization of electron charge affects plasmon behavior.

Abstract

We consider theoretically as a function of temperature the plasmon mode arising in three-dimensional Dirac liquids, i.e., systems with linear chiral relativistic single-particle dispersion, within the random phase approximation. We find that whereas no plasmon mode exists in the intrinsic (undoped) system at zero temperature, there is a well-defined finite-temperature plasmon with superlinear temperature dependence, rendering the plasmon dispersion widely tunable with temperature. The plasmon dispersion contains a logarithmic correction due to the ultraviolet-logarithmic renormalization of the electron charge, manifesting a fundamental many-body interaction effect as in quantum electrodynamics. The plasmon dispersion of the extrinsic (doped) system displays a minimum at finite temperature before it crosses over to the superlinear intrinsic behavior at higher temperature, implying that the high-temperature plasmon is a universal feature of Dirac liquids irrespective of doping. This striking characteristic temperature dependence of intrinsic Dirac plasmons along with the logarithmic renormalization is a unique manifestation of the three-dimensional relativistic Dirac nature of quasiparticle excitations and serves as an experimentally observable signature of three-dimensional Dirac materials.