Fig. 3: Proximity-induced anisotropy and uniaxial SPPs in graphene/CrSBr heterostructures.
From: Engineering anisotropic electrodynamics at the graphene/CrSBr interface
A Map of the near-field S4 amplitude in a graphene/CrSBr heterostructure showing multiple SPP fringes propagating along the CrSBr a-axis, while b-axis fringes are highly suppressed. Inset: The average line profiles of SPP fringes along the a-axis (red curve) versus the b-axis (blue curve) show a significantly diminished decay length for the latter (ω = 880 cm–1; S4 normalized relative to the value in the graphene/CrSBr bulk). B The experimentally-extracted frequency-dependent Q-factor for SPPs propagating along the a-axis (red circles) and b-axis (blue circles). Error bars are extracted from the standard error of \({q}_{1}\) and \({q}_{2}\) when fitting the line profiles in Fig. S3. C Left panel: Space-time map of the near-field plasmon electric field (\(\Delta {E}_{{NF}}\)) conducted along the a-axis of a graphene/CrSBr heterostructure (See Fig. S7 for background subtraction procedure). The edges of the images correspond to the edges of CrSBr. The red arrows indicate extrema that correspond to the worldlines of propagating SPPs. The group velocity of a-axis modes \({v}_{g}^{a}\) is twice the slope of the worldline. Right panel: The same as the left panel but for b-axis propagating modes with blue arrows indicating the SPP worldlines with group velocity \({v}_{g}^{b}\). D Histograms of the associated values of \({v}_{g}^{a}\) (red bars) and \({v}_{g}^{b}\) (blue bars) extracted from N ≥ 18 worldlines for each direction showing a systematic suppression of \({v}_{g}^{b}\) compared to \({v}_{g}^{a}\).
