Improved modeling of Coulomb effects in nanoscale Schottky-barrier FETs

TL;DR

This paper introduces a multi-configurational self-consistent Green's function method for simulating nanoscale Schottky-barrier FETs, capturing Coulomb effects across different regimes from single-electron to room temperature operation.

Contribution

The novel MCSCG approach divides the channel into a resonant subsystem and a mean-field rest, enabling accurate Coulomb charging effect calculations beyond mean-field approximations.

Findings

Coulomb blockade effects are demonstrated at low temperatures.

The MCSCG method captures Coulomb effects beyond mean-field.

The approach seamlessly transitions from single-electron to room temperature regimes.

Abstract

We employ a novel multi-configurational self-consistent Green's function approach (MCSCG) for the simulation of nanoscale Schottky-barrier field-effect transistors. This approach allows to calculate the electronic transport with a seamless transition from the single-electron regime to room temperature field-effect transistor operation. The particular improvement of the MCSCG stems from a division of the channel system into a small subsystem of resonantly trapped states for which a many-body Fock space becomes feasible and a strongly coupled rest which can be treated adequately on a conventional mean-field level. The Fock space description allows for the calculation of few-electron Coulomb charging effects beyond mean-field. We compare a conventional Hartree non-equilibrium Green's function calculation with the results of the MCSCG approach. Using the MCSCG method Coulomb blockade effects are demonstrated at low temperatures while under strong nonequilibrium and room temperature conditions the Hartree approximation is retained.