Collective plasmonic modes in the chiral multifold fermionic material CoSi

Abstract

Plasmonics in topological semimetals offers exciting opportunities for fundamental physics exploration as well as for technological applications. Here, we investigate plasmons in the exemplar chiral crystal CoSi, which hosts a variety of multifold fermionic excitations. We show that CoSi hosts two distinct plasmon modes in the infrared regime at 0.1 eV and 1.1 eV in the long-wavelength limit. The 0.1 eV plasmon is found to be highly dispersive, and originates from intraband collective oscillations associated with a double spin-1 excitation, while the 1.1 eV plasmon is dispersionless and it involves interband correlations. Both plasmon modes lie outside the particle-hole continuum and possess long lifetime. Our study indicates that the CoSi class of materials will provide an interesting materials platform for exploring fundamental and technological aspects of topological plasmonics.

References in corpus (17)

• Graphene plasmonics
• Topological nodal line semimetals
• Multiple types of topological fermions in transition metal silicides
• Large Fermi Arcs in Unconventional Weyl Semimetal RhSi
• New classes of chiral topological nodes with non-contractible surface Fermi arcs in CoSi
• Collective modes of the massless Dirac plasma
• Linear density response function in the projector-augmented wave method: Applications to solids, surfaces, and interfaces
• Plasmon mode as a detection of the chiral anomaly in Weyl semimetals
• Electron Energy-Loss Spectroscopy: A versatile tool for the investigations of plasmonic excitations
• Plasmon signature in Dirac-Weyl liquids
• Quasiparticle Interference Evidence of the Topological Fermi Arc States in Chiral Fermionic Semimetal CoSi
• Long-lived spin plasmons in a spin-polarized two-dimensional electron gas
• Linear optical conductivity of chiral multifold fermions
• Dynamic current-current susceptibility in 3D Dirac and Weyl semimetals
• Plasmon modes of a massive Dirac plasma, and their superlattices
• Tunable Intrinsic Plasmons due to Band Inversion in Topological Materials
• Plasmons in spin polarized graphene: a new way to measure spin polarization