Tunneling resonances in quantum dots: Coulomb interaction modifies the width

Abstract

Single-electron tunneling through a zero-dimensional state in an asymmetric double-barrier resonant-tunneling structure is studied. The broadening of steps in the I-V characteristics is found to strongly depend on the polarity of the applied bias voltage. Based on a qualitative picture for the finite-lifetime broadening of the quantum dot states and a quantitative comparison of the experimental data with a nonequilibrium transport theory, we identify this polarity dependence as a clear signature of Coulomb interaction. © 2006 The American Physical Society.