Charge-Transfer Plasmon Polaritons at Graphene/α-RuCl₃ Interfaces

Abstract

Nanoscale charge control is a key enabling technology in plasmonics, electronic band structure engineering, and the topology of two-dimensional materials. By exploiting the large electron affinity of α-RuCl 3 , we are able to visualize and quantify massive charge transfer at graphene/α-RuCl 3 interfaces through generation of chargetransfer plasmon polaritons (CPPs). We performed nanoimaging experiments on graphene/α-RuCl 3 at both ambient and cryogenic temperatures and discovered robust plasmonic features in otherwise ungated and undoped structures. The CPP wavelength evaluated through several distinct imaging modalities offers a high-fidelity measure of the Fermi energy of the graphene layer: E F = 0.6 eV (n = 2.7 × 10 13 cm −2 ). Our first-principles calculations link the plasmonic response to the work function difference between graphene and α-RuCl 3 giving rise to CPPs. Our results provide a novel general strategy for generating nanometer-scale plasmonic interfaces without resorting to external contacts or chemical doping.

Harnessing ultraconfined graphene plasmons to probe the electrodynamics of superconductors

“… 25 and 32 , while the former approach can still be pursued using cutting-edge electron-beam lithography ( 61 ). Another possibility is the use of highly localized, local back-gate-free graphene doping modulation by placing a pristine graphene sheet on a substrate with patterned - ( 62 ).…”

“…3; the energy has been fixed at the value ω H . localized, local back-gate-free graphene doping modulation by placing a pristine graphene sheet on a substrate with patterned α-RuCl3 (62).…”

Nanometer-Scale Lateral p–n Junctions in Graphene/α-RuCl3 Heterostructures

“…The oscillatory nature of the near-field signal moving radially from nanobubbles is consistent with the presence of SPPs that are either being launched or reflected from these locations, giving rise to modulations in the near-field signal that extend far beyond the nanobubble area. It has been suggested that these plasmonic features arise due to discontinuities in the graphene conductivity associated with local modulation of charge carrier density, 22 though the precise nature of this profile demands further scrutiny with STM and STS.…”

“…Previous work on similar heterostructures would suggest the near-field behavior is primarily dominated by the latter. 22 …”

Flavoured quantum Hall phase in graphene/CrOCl heterostructures

“…Interestingly, the observed SIC-QHE phase seems to have no connection to the anti-ferromagnetic nature of CrOCl itself, as the Néel temperature of it is only ∼14 K, way lower than the upper bound temperature for the SIC-QHE phase. Recently, charge transfer phenomena have been also found in such as RuCl 3 /graphene systems, which give rise to a shifting of Raman signal or plasmonic characteristics in graphene, and seem to be often irrelevant to the magnetic order of the Cl-based substrates [40,41]. Those other Cl-based compounds are reported to lead to inferior mobilities in the resulted hybrid systems, and are not suitable for QHE studies [25,26].…”