Journal ArticleImaging and simulation of surface plasmon polaritons on layered 2D MXenesRieger, Janek; Ghosh, Atreyie; Spellberg, Joseph L; Raab, Calvin; Mohan, Aishani; Joshi, Prakriti P; King, Sarah B<p>Two-dimensional (2D) transition metal carbides and nitrides, commonly known as MXenes, are a class of 2D materials with high free carrier densities, making them highly attractive candidates for plasmonic 2D materials. In this study, we use multiphoton photoemission electron microscopy (<italic>n</italic>P-PEEM) to directly image the plasmonic near fields of multilayers of the prototypical MXene, Ti₃C₂T<italic>_x</italic>, with mixed surface terminations (T<italic>_x</italic> = F, O, and OH). Photon-energy dependent<italic>n</italic>P-PEEM reveals a dispersive surface plasmon polariton between 1.4 and 1.9 electron volts on MXene flakes thicker than 30 nanometers and waveguide modes above 1.9 electron volts. Combining experiments with finite-difference time-domain simulations, we reveal the emergence of a visible surface plasmon polariton in MXenes, opening avenues for exploration of polaritonic phenomena in MXenes in the visible portion of the electromagnetic spectrum.</p>American Association for the Advancement of Science2025-03-2110590258Science Advances11122375-2548https://doi.org/10.1126/sciadv.ads36892011854; 2318105National Science Foundation