Electromagnetic simulation of MXene-based plasmonic metamaterials with enhanced optical absorption

In this contribution we propose, design and numerically analyze a plasmonic metamaterial for enhanced optical absorption, based on 100 nm thick titanium carbide (Ti₃C₂T_x) MXene sheets. The analyzed metamaterial is built as a sandwich with a solid MXene bottom (ground) layer, a lossless dielectric middle layer and an MXene mesh top layer. The unit cell of the periodic top mesh consists of two crossed ultrathin MXene strips, each of them spreading its width in step-like increments towards the middle of the unit cell. This ensures position-variable width of the top surface apertures, resulting in a widening of the bandwidth of spectral dispersion of the scattering parameters of the obtained metamaterial. We utilize the finite element method to simulate the scattering parameters of the MXene-based metamaterial. We apply Drude–Lorentz model to derive our analytical expression for complex permittivity of Ti₃C₂T_x MXene based on experimental measurements. The described approach is general, since various alternative plasmonic materials can be utilized, including different MXenes, but other materials as well, such as graphene, metals and metal alloys, semiconductors, etc. The approach is applicable to various other nanoplasmonic structures. In this manner the available toolbox for plasmonics is extended and a new degree of design freedom ensured.