Plasmons in coupled bilayer structures

TL;DR

This paper investigates how interlayer tunneling affects plasmon modes in bilayer semiconductor structures, revealing a tunneling-dependent gap in the out-of-phase mode that can aid in studying many-body effects.

Contribution

It provides a theoretical analysis of plasmon dispersion in coupled bilayer structures including tunneling effects, highlighting the tunneling-induced gap in the out-of-phase mode.

Findings

Out-of-phase plasmon develops a tunneling-dependent gap.

In-phase plasmon remains unaffected by tunneling.

The gap's dependence on tunneling amplitude is characterized.

Abstract

We calculate the collective charge density excitation dispersion and spectral weight in bilayer semiconductor structures {\it including effects of interlayer tunneling}. The out-of-phase plasmon mode (the ``acoustic'' plasmon) develops a long wavelength gap in the presence of tunneling with the gap being proportional to the square root (linear power) of the tunneling amplitude in the weak (strong) tunneling limit. The in-phase plasmon mode is qualitatively unaffected by tunneling. The predicted plasmon gap should be a useful tool for studying many-body effects.