Fig. 3

Experimental observation of topological kink magnetoplasmons (KMPs). a and b Measured power transmission \({S}_{21}\) (normalized to indicated baselines) as a function of frequency for a, varying applied uniform fields \({B}_{0}\) (\(V_{\mathrm{{g}}}=\text{0 V}\)) and b, varying gate voltages \(V_{\mathrm{g}}\) (\({B}_{0}=\text{0 T}\)). The characteristic absorption dips correspond to quasi-even KMPs with angular wavenumber \(m=\text{1}\) and 2, as indicated. Insets depict the (idealized) total magnetic field profile \(B(r)\) across the domains, as well as the measured dependence of the electron concentration \({n}_{0}\) with \(V_{\mathrm{g}}\) (from independent Hall transport measurements). c and d Comparison between experimental observations and theoretical calculations. Dependence of KMP frequencies with c, applied field \({B}_{0}\) (\(V_{\mathrm{g}}=\text{0 V}\), \({n}_{0}=\text{1}\times {\text{10}}^{\text{11}}\ {{\rm{cm}}}^{-\text{2}}\)) and d electron concentration \({n}_{0}\) (\({B}_{0}=\text{0 T}\))