arXiv.svg (5.58 kB)
Low-loss forward and backward surface plasmons in a semiconductor nanowire coated by helical graphene strips
preprintposted on 2023-11-30, 05:44 authored by Vitalii I. Shcherbinin, Volodymyr I. Fesenko, Vladimir R. Tuz
In the long-wavelength approximation, the effective conductivity tensor is introduced for graphene ribbons (strips) placed periodically at the interface between two media. The resulting conducting surface is considered as a coating for semiconductor nanowire. For the hybrid waves of such nanowire the dispersion equations are obtained in explicit form. Two types of surface plasmons are found to exist: (i) the modified surface plasmons, which originate from the ordinary surface plasmons of a graphene-coated semiconductor nanowire, and (ii) the spoof plasmons, which arise on the array of graphene ribbons and may possess forward-wave and backward-wave dispersion. It is revealed that the spoof surface plasmons are low-loss ones, and their frequencies, field-confinement and group velocities can be tuned widely by adjusting the coil angle and width of helical graphene strips.