Microscopic theory of electron cotunneling through quantum dots

Abstract

A microscopic theory is presented for electron cotunneling through quantum dots in the Coulomb blockade regime. Beyond the semiclassic framework of phenomenological models, a fully quantum mechanical solution for cotunneling of electrons through a one-dimensional quantum dot is obtained by using a quantum transmitting boundary method without any fitting parameters. Elastic and inelastic cotunneling conductance is calculated as a function of the energy of the incident electron. It is revealed that the cotunneling current contains a significant term proportional to V2 (V being the bias voltage) in additional to the well-known V3 term. The result also indicates that the cotunneling conductance exhibits little dependence on the spin configuration of the incident and confined electrons.

Observation of room temperature negative differential resistance in multi-layer heterostructures of quantum dots and conducting polymers

“…Due to quantum confinement, quantum dots, sometimes called 'artificial atoms', have discrete electronic levels that shift to higher energies with decreasing size [7]. A full quantum mechanical solution of tunneling of electrons through the quantum dot in the Coulomb blockade regime has been investigated very recently [8]. In a double barrier structure, the discrete quantum confined states aligned with the Fermi level of the emitter can lead to sharp current peaks and NDR.…”

Electron cotunneling through doubly occupied quantum dots: effect of spin configuration

“…Actually, the conductance is seen to be almost linear with the bias voltage with a very small quadratic term. For comparison, the conductance of electron cotunneling through a singly occupied quantum dot exhibits very little dependence on the spin configuration of the incident and confined electrons [ 14 ]. Furthermore, it exhibits much less deviation from the quadratic dependence than the cotunneling conductance for the triplet configuration.…”