Improved modeling of Coulomb effects in nanoscale Schottky-barrier FETs

We employ a novel multi-configurational selfconsistent 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.