Electromagnetic screening of plasmons in a two-dimensional electron system by lateral and topside gates

In this paper, we calculate the frequencies of the plasmon resonances in 2DES with lateral and topside metal gates (see Fig. 1) in a self-consistent electromagnetic approach. In the structure with lateral gates (right insert in Fig. 1), the resonant cavity for plasmons in 2DES is formed by the edges of metal lateral gates separated from each other by distance w. We normalize the frequency of the plasmon resonance in 2DES with lateral metal gates by comparing it with the plasmon frequency ω₀ in ungated 2DES, which are given by Eq. (1) with the effective dielectric function ε = (1 + ε_s)/2, assuming the plasmon wavevector to be q = 2.2/w with w being the separation between the lateral gates. This effective plasmon wavevector describes the fundamental plasmon mode in ungated 2DES strip.