Work function-mediated charge transfer in graphene/α-RuCl3 heterostructures has been proposed as a strategy for generating highly-doped 2D interfaces. In this geometry, graphene should become sufficiently doped to host surface and edge plasmon-polaritons (SPPs and EPPs, respectively). Characterization of the SPP and EPP behavior as a function of frequency and temperature can be used to simultaneously probe the magnitude of interlayer charge transfer while extracting the optical response of the interfacial doped α-RuCl3. We accomplish this using scanning near-field optical microscopy (SNOM) in conjunction with first-principles DFT calculations. This reveals massive interlayer charge transfer (2.7 × 1013 cm−2) and enhanced optical conductivity in α-RuCl3 as a result of significant electron doping. Our results provide a general strategy for generating highly-doped plasmonic interfaces in the 2D limit in a scanning probe-accessible geometry without need of an electrostatic gate.
@article{arxiv.2007.07147,
title = {Graphene/$\alpha$-RuCl$_3$: An Emergent 2D Plasmonic Interface},
author = {Daniel J. Rizzo and Bjarke S. Jessen and Zhiyuan Sun and Francesco L. Ruta and Jin Zhang and Jia-Qiang Yan and Lede Xian and Alexander S. McLeod and Michael E. Berkowitz and Kenji Watanabe and Takashi Taniguchi and Stephen E. Nagler and David G. Mandrus and Angel Rubio and Michael M. Fogler and Andrew J. Millis and James C. Hone and Cory R. Dean and D. N. Basov},
journal= {arXiv preprint arXiv:2007.07147},
year = {2020}
}