Plasmonics in topological semimetals offer 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 and 1.1 eV in the long-wavelength limit. The 0.1 eV plasmon is found to be highly dispersive, and it 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 a 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. © 2022 American Physical Society.

Collective plasmonic modes in the chiral multifold fermionic material CoSi

Politano, A.
Supervision
;
2022-01-01

Abstract

Plasmonics in topological semimetals offer 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 and 1.1 eV in the long-wavelength limit. The 0.1 eV plasmon is found to be highly dispersive, and it 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 a 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. © 2022 American Physical Society.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/191200
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