SIMULATION OF QUANTUM TRANSPORT IN QUANTUM DEVICES WITH SPATIALLY VARYING EFFECTIVE MASS

The precise simulation of quantum transport in quantum size structures has become more important with the recent progress of crystal growth technology. In this paper, we present some novel progress in quantum-mechanical simulation based on the Wigner function model. An exact nonlocal formulation in the Wigner representation due to a spatially varying effective mass and its discretization for numerical calculation are discussed for the first time. To verify the validity of such a formulation, the current-voltage characteristics of resonant tunneling diodes are simulated to compare with the conventional Wigner function model. We also point out the importance of the self-consistent calculation in the electrostatic potential for precise device simulation. Finally, we emphasize that the Wigner function model is superior to the alternative method based on the transmission probability method even for the static simulation of quantum transport.