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Intrinsically undamped plasmon modes in narrow electron bands.

ABSTRACT: Surface plasmons in 2-dimensional electron systems with narrow Bloch bands feature an interesting regime in which Landau damping (dissipation via electron-hole pair excitation) is completely quenched. This surprising behavior is made possible by strong coupling in narrow-band systems characterized by large values of the "fine structure" constant [Formula: see text] Dissipation quenching occurs when dispersing plasmon modes rise above the particle-hole continuum, extending into the forbidden energy gap that is free from particle-hole excitations. The effect is predicted to be prominent in moiré graphene, where at magic twist-angle values, flat bands feature [Formula: see text] The extinction of Landau damping enhances spatial optical coherence. Speckle-like interference, arising in the presence of disorder scattering, can serve as a telltale signature of undamped plasmons directly accessible in near-field imaging experiments.

SUBMITTER: Lewandowski C

PROVIDER: S-EPMC6800336 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Intrinsically undamped plasmon modes in narrow electron bands.

Lewandowski Cyprian C Levitov Leonid L

Proceedings of the National Academy of Sciences of the United States of America 20190927 42

Surface plasmons in 2-dimensional electron systems with narrow Bloch bands feature an interesting regime in which Landau damping (dissipation via electron-hole pair excitation) is completely quenched. This surprising behavior is made possible by strong coupling in narrow-band systems characterized by large values of the "fine structure" constant [Formula: see text] Dissipation quenching occurs when dispersing plasmon modes rise above the particle-hole continuum, extending into the forbidden ener ...[more]

PMID: 31562197

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