A Reduced-Order Method for Coherent Transport Using Green’s Functions

A reduced-order method is presented to efficiently calculate Green´s functions connecting contacts or leads to all the points in a nanostructure in the coherent transport limit. The proposed approach samples a small subset of spatial grid points on the lead and a small subset of energy grid points to build a reduced-order model. The efficacy of the algorithm is demonstrated by applying it to calculate both the electron density and transmission in a resonant tunneling structure, a MOSFET, and a bilayer graphene device. The match in features of both the electron density and transmission versus energy with conventional methods to model devices is excellent while a large reduction in computational time is demonstrated.