Plasmons in Coupled Bilayer Structures

O ct 1 99 8 Plasmons in coupled bilayer structures

We calculate the collective charge density excitation dispersion and spectral weight in bilayer semiconductor structures 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) tunn...

Transverse electric plasmons in bilayer graphene.

We predict the existence of transverse electric (TE) plasmons in bilayer graphene. We find that their plasmonic properties are much more pronounced in bilayer than in monolayer graphene, in a sense that they can get more localized at frequencies just below ħω = 0.4 eV for adequate doping values. This is a consequence of the perfectly nested bands in bilayer graphene which are separated by ∼ 0.4...

Exchange bias training effect in coupled all ferromagnetic bilayer structures.

Exchange coupled bilayers of soft and hard ferromagnetic thin films show remarkable analogies to conventional antiferromagnetic/ferromagnetic exchange bias heterostructures. Not only do all these ferromagnetic bilayers exhibit a tunable exchange bias effect, they also show a distinct training behavior upon cycling the soft layer through consecutive hysteresis loops. In contrast with conventiona...

Coupled magnetic plasmons in metamaterials

Dielectric screening and plasmons in AA-stacked bilayer graphene

The screening properties and collective excitations (plasmons) in AA-stacked bilayer graphene are studied within the random phase approximation. Whereas long-lived plasmons in single-layer graphene and in AB-stacked bilayer graphene can exist only in doped samples, we find that coherent plasmons can disperse in AA-stacked bilayer graphene even in the absence of doping. Moreover, we show that th...