Plasmons and screening in finite-bandwidth two-dimensional electron gas

Kaveh Khaliji, Tobias Stauber, Tony Low

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The dynamical and nonlocal dielectric function of a two-dimensional electron gas with finite-energy bandwidth is computed within a random-phase approximation. For large bandwidth, the plasmon dispersion has two separate branches at small and large momenta. The large-momenta branch exhibits negative quasiflat dispersion. The two branches merge with decreasing bandwidth. We discuss how the maximum-energy plasmon mode, which resides at energies larger than all particle-hole continuum, can potentially open a route to low-loss plasmons. Moreover, we discuss the bandwidth effects on the static screening of the charged and magnetic impurities.

Original languageEnglish (US)
Article number125408
JournalPhysical Review B
Issue number12
StatePublished - Sep 2020

Bibliographical note

Funding Information:
This work has been supported by Spain's MINECO under Grant No. FIS2017-82260-P as well as by the CSIC Research Platform on Quantum Technologies, Grant No. PTI-001. K.K. and T.L. acknowledge support by the National Science Foundation NSF/EFRI Grant No. EFRI-1741660.

Publisher Copyright:
© 2020 American Physical Society.

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