Oscillatory magnetotransport between co-propagating quantum Hall edge channels in graphene p-n junctions

We conducted magnetotransport measurements in high-quality dual-gated graphene n-p-n junctions. As we used hexagonal boron nitride as a dielectric layer, Fabry-Perot interference patterns\footnote{A. F. Young \textsl{et al}., \textbf{Nat. Phys.} 5, 222.} can be observed clearly in zero magnetic fields, owing to the extremely high carrier mobility of our devices.\footnote{S. Masubuchi, S. Morikawa \textsl{et al}., \textbf{Jpn J. Appl. Phys.} 52, 110105.} Moreover, the two-terminal resistance $R$ exhibited oscillatory behavior as a function of the magnetic field $B$, whose oscillation period $\Delta B$ differed from both the conventional Shubnikov-de Haas effect ($\Delta B \propto B$) and the Aharonov-Bohm effect with magnetic flux penetrating through the gated region ($\Delta B = \mathrm{const}$). The oscillatory behavior of $R$ was well reproduced by our numerical calculation under the assumption that $R$ oscillated as a function of the magnetic flux penetrating through the insulating region between the co-propagating p and n quantum Hall edge channels.\footnote{S. Morikawa \textsl{et al}., submitted.}