Charge and Spin Effects in Quantum Antidot Tunneling

Vladimir J. Goldman

SUNY, USA

Quantum antidot, a small potential hill introduced into a two-dimensional electron system, presents an attractive tool to study quantum mechanics of interacting electrons. In experiments on resonant tunneling through a quantum antidot in the quantum Hall regime we observe periodic conductance peaks both versus magnetic field and a global gate voltage, i.e., electric field. Each conductance peak can be attributed to tunneling through a quantized antidot-bound state. The fact that application of a uniform electric field produces conductance peaks implies that the deficiency of the electrical charge on the antidot is quantized in units of charge of quasiparticles of surrounding QH incompressible condensate. The period in magnetic field gives the effective area of the antidot state through which tunneling occurs; the period in electric field then constitutes a direct measurement of the charge of the tunneling particles.