Quantum Mechanical Simulation of Electronic Transport in Nanostructured Devices by Efficient Self-consistent Pseudopotential Calculation

摘要

We present a new empirical pseudopotential (EPM) calculation approach tosimulate the million atom nanostructured semiconductor devices under potentialbias using the periodic boundary conditions. To treat the non-equilibriumcondition, instead of directly calculating the scattering states from thesource and drain, we calculate the stationary states by the linear combinationof bulk band method and then decompose the stationary wave function into sourceand drain injecting scattering states according to an approximated top of thebarrier splitting (TBS) scheme based on physical insight of ballistic andtunneling transport. The decomposed electronic scattering states are thenoccupied according to the source/drain Fermi-Levels to yield the occupiedelectron density which is then used to solve the potential, forming aself-consistent loop. The TBS is tested in an one-dimensional effective massmodel by comparing with the direct scattering state calculation results. It isalso tested in a three-dimensional 22 nm double gate ultra-thin-bodyfield-effect transistor study, by comparing the TBS-EPM result with thenon-equilibrium Green's function tight-binding result. We expected the TBSscheme will work whenever the potential in the barrier region is smoother thanthe wave function oscillations and if it does not have local minimum, thusthere is no multiple scattering as in a resonant tunneling diode, and when athree-dimensional problem can be represented as a quasi-one-dimensionalproblem, e.g., in a variable separation approximation. Using our approach, amillion atom non-equilibrium nanostructure device can be simulated with EPM ona single processor computer.