Acoustic plasmons at the crossover between collisionless and hydrodynamic regimes

Date: 3 March 2020

Venue: Campus Groenenborger, Building U, Room 244 - Groenenborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger)

Time: 4:00 PM

Organization / co-organization: Condensed Matter Theory

Short description: CMT Lecture presented by Dr. Ban Van Duppen

Hydrodynamic flow in two-dimensional electron systems has so far been probed only by dc transport and scanning gate microscopy measurements. In this talk, I discuss theoretically signatures of the hydrodynamic regime in near-field optical microscopy.

I analyze the dispersion of acoustic plasmon modes in two-dimensional electron liquids using a non-local conductivity that takes into account the effects of (momentum-conserving) electron-electron collisions, (momentum-relaxing) electron-phonon and electron-impurity collisions, and many-body interactions beyond the celebrated Random Phase Approximation.

I derive the dispersion and, most importantly, the damping of acoustic plasmon modes and their coupling to a near-field probe, identifying key experimental signatures of the crossover between collisionless and hydrodynamic regimes. Finally, I discuss how the used mechanism is also perfectly suitable for treating the systems in the presence of perturbative magnetic fields.

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