Imaging transport resonances in the quantum Hall effect.
We use a scanning capacitance probe to image transport in the quantum Hall system. Applying a dc bias voltage to the tip induces a ring-shaped incompressible strip (IS) in the 2D electron system (2DES) that moves with the tip. At certain tip positions, short-range disorder in the 2DES creates a quantum dot island in the IS. These islands enable resonant tunneling across the IS, enhancing its conductance by more than 4 orders of magnitude. The images provide a quantitative measure of disorder and suggest resonant tunneling as the primary mechanism for transport across ISs.
Steele
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GA
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Ashoori
R C
RC
Pfeiffer
L N
LN
West
K W
KW