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Insulating state and giant nonlocal response in an InAs/GaSb quantum well in the quantum Hall regime.

Research paper by Fabrizio F Nichele, Atindra Nath AN Pal, Patrick P Pietsch, Thomas T Ihn, Klaus K Ensslin, Christophe C Charpentier, Werner W Wegscheider

Indexed on: 04 Feb '14Published on: 04 Feb '14Published in: Physical review letters



Abstract

We present transport measurements performed in InAs/GaSb double quantum wells. At the electron-hole crossover tuned by a gate voltage, a strong increase in the longitudinal resistivity is observed with increasing perpendicular magnetic field. Concomitantly with a local resistance exceeding the resistance quantum by an order of magnitude, we find a pronounced nonlocal resistance signal of almost similar magnitude. The coexistence of these two effects is reconciled in a model of counterpropagating and dissipative quantum Hall edge channels providing backscattering, shorted by a residual bulk conductivity.