Suppression of the equilibrium tunneling current between slightly disordered two-dimensional electron systems with different electron concentrations in a high magnetic field
Dubrovskii Yu.V., Vdovin E.E., Khanin Yu.N., Popov V.G., Maude D.K., Portal J.-C., Maan J.K., Andersson T.G., Wang S.
PACS: 73.20.Dx, 73.40.Gx
Tunnelling between parallel two-dimensional electron gases (2DEG) in accumulation layers formed on both sides of the single doped AlGaAs barrier are examined in both zero and high magnetic field. Accumulation layers are separated from highly η-doped contact regions which freely supply electrons to the 2DEGs via 80 nm thick lightly η-doped spacer layers. Strongly oscillating current with magnetic field along the 2DEG's is absent in this arrangement. Without magnetic field resonant tunneling between 2DEGs with different as grown electron concentration could be settle by application of external voltage bias. High magnetic fields (u < 1) shift resonant tunnelling to zero external bias and suppresses tunnelling current, creating wide gap in the tunneling density of states at the Fermi level arisen from the in-plane Coulomb interaction in the 2DEGs.