Gradec, Slovenija : Fakulteta za tehnologijo polimerov
Abstract
In our recent publication1 we have studied the wake potential induced by an external charged particle that moves parallel to various sy1-Al2O3-sy2 composites, where syi (with i=1,2) may be vacuum, pristine graphene, or doped graphene. Several important parameters were fixed at their respective typical values: the distance of the charged particle from the closest surface, the thickness of the sapphire (aluminum oxide, Al2O3) layer, and the doping density (i.e., Fermi energy) of graphene. In this work we present a detailed study of the effects due to variations of all those parameters in the case of the wake potential produced by charged particle moving parallel to the graphene-Al2O3- graphene composite system, by using the dynamic polarization function of graphene within the random phase approximation for its π electrons described as Dirac’s fermions and by using a local dielectric function for the sapphire layer2 . For the velocity of the charged particle below the threshold for excitations of the Dirac plasmon in graphene, given by its Fermi velocity vF, strong effects are observed due to variation of the particle distance, while for the velocity of the charged particle above vF strong effects are observed due to varying the thickness of the Al2O3 layer, as well as due to graphene doping
