A novel undamped gapless plasmon mode in tilted type-II Dirac semimetal

We predict the existence of a novel long-lived gapless plasmon mode in a type-II Dirac semimetal (DSM). This gapless mode arises from the out-of-phase oscillations of the density fluctuations in the electron and the hole pockets of a type-II DSM. It originates beyond a critical wave-vector along the...

Full description

Saved in:
Bibliographic Details
Published inarXiv.org
Main Authors Sadhukhan, Krishanu, Politano, Antonio, Agarwal, Amit
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 23.04.2019
Subjects
Fermi surfaces
Landau damping
Momentum
Physics - Mesoscale and Nanoscale Physics
Variations
Online AccessGet full text

Cover

More Information
Summary:We predict the existence of a novel long-lived gapless plasmon mode in a type-II Dirac semimetal (DSM). This gapless mode arises from the out-of-phase oscillations of the density fluctuations in the electron and the hole pockets of a type-II DSM. It originates beyond a critical wave-vector along the direction of the tilt axis, owing to the momentum separation of the electron and hole pockets. A similar out-of-phase plasmon mode arises in other multi-component charged fluids as well, but generally it is Landau damped and lies within the particle-hole continuum. In the case of a type-II DSM, the open Fermi surface prohibits low-energy finite momentum single-particle excitations, creating a `gap' in the particle-hole continuum. The gapless plasmon mode lies within this particle-hole continuum gap and, thus, it is protected from Landau damping.
ISSN:2331-8422
DOI:10.48550/arxiv.1904.10137