Large-scale first-principles quantum transport simulations using plane wave basis set on high performance computing platforms

Abstract

As the characteristic lengths of advanced electronic devices are approaching the atomic scale, ab initio simulation method, with full consideration of quantum mechanical effects, becomes essential to study the quantum transport phenomenon in them. The widely used non-equilibrium Green’s function (NEGF) combined with the density functional theory (DFT) approach prefers a localized basis set. As many states of the art DFT calculations for solid state systems are carried out in plane waves, it is thus worth to investigate the feasibility of using the plane wave basis set for large-scale quantum transport calculations. Here we present a plane wave method for large-scale transport calculations based on a previously developed scattering state calculation approach (Wang, 2005). We address the unique computational challenges of applying that approach for large-scale systems where it is too expensive to calculate all the occupied eigenstates of the system as in conventional DFT calculations. By applying several high-efficiency parallel algorithms, including linear-scaling DFT algorithm, folded spectrum method, and Chebyshev filter technique, we demonstrate that it is possible to use this approach to simulate a system with several thousand atoms on high performance computing platforms. This method is not only used to study nanowire interconnects, showing how the shape and point defect affects their transport properties, but also used to study nanoscale Si transistor. Such quantum transport simulation method will be useful for investigating and designing nanoscale devices.