Speeding up tight binding calculations using zone-folding methods

Tight binding models are widely used in large scale electronic structure calculations of nanostructures. Their atomistic nature makes them flexible, but also means the computational cost increases rapidly with system size. The large number of calculations required to design nanostructures makes computational efficiency desirable. We have developed a method to increase computational speed while retaining most of its accuracy. The method is based on the use of supercells and zone folding combined with a truncation of the Hamiltonians to only include states close to the band-edges. We apply the method to model the band edge energies of a GaAs/AlAs quantum well grown along the [110]-directions with 3D and 2D periodic boundary conditions as well as the density of states and dielectric function of the quantum well. We typically find a speed-up of ten times with only a small loss of accuracy of the calculation result.

Automated summary

Tight binding models are commonly used in electronic structure calculations of nanostructures. In order to enhance computational efficiency, we propose a method that utilizes supercells, zone folding, and truncation of the Hamiltonians. Through experiments on a GaAs/AlAs quantum well, we find that this method significantly increases computational speed while only sacrificing a small measure of accuracy.