Calculation of self-energy matrices using complex absorbing potentials in electron transport calculations

A method is presented to evaluate self-energy matrices used in the Green's function formulation of transport calculations. By adding a complex absorbing potential to the Hamiltonian of a semi-infinite lead, the problem of inverting an infinite-dimensional matrix is transformed into a finite-dimensional eigenvalue problem. The self-energies are calculated for all energies at once and can be tabulated for a given system. Examples are presented to show the accuracy of the approach.