Collective plasmonic oscillations of zigzag boron-nitride nanotubes in the presence of Holstein phonons

Abstract

In this paper, we study theoretically both dynamical and static charge susceptibilities of zigzag boron-nitride nanotube due to the effects of electron-phonon interaction. One can find the plasmonic oscillation modes of the system using the imaginary part of the dynamical charge susceptibility function. For this purpose, we implement Green's function approach in the context of the Holstein model Hamiltonian. According to the linear response theory, the charge response function will be obtained by calculating the correlation function of charge density-density operators. We also exploit the random phase approximation in order to correct the charge susceptibility due to the electron-phonon interaction. In addition, we present the static charge structure factor which can be a criterion for charge ordering of the system. Especially the effect of electron-phonon coupling, gap parameter, chemical potential, next-to-nearest-neighbor hopping amplitude, and tube diameter on the plasmonic modes of the system. The results indicate a change in the intensity, frequency position of sharp peaks, and the number of those in the imaginary part of the dynamical charge susceptibility function of zigzag boron-nitride nanotube system. Finally, the temperature behavior of the static charge structure factor of zigzag boron-nitride nanotube is studied and the effect of the mentioned parameters on this function has been investigated.