An ADHIE-TDDFT Method for the EM/QM Co-simulation of Coupled 1-D Nanowires

Over the past years, the rapid increase in device functionality and miniaturization has stimulated the demand for novel topologies and materials. One such trend is the emergence of one-dimensional nanostructures in electronic components. Given the embryonic stage of these applications, adequate modeling tools should be developed to investigate the structures' intricate dynamics. This encompasses the interplay of the charge carriers, described by the laws of quantum mechanics (QM), with external and self-generated electromagnetic (EM) fields. However, the EM/QM co-simulation of those systems is challenging owing to the multiscale and multiphysics aspects of the problem. In this work, we improve upon existing modeling techniques by invoking an alternating-direction hybrid implicit-explicit (ADHIE) scheme for the EM potentials. The dynamics of the charge carriers in the quantum system are described through the time-dependent density functional theory (TDDFT) formalism, discretized on the real-space grid. The new technique is put to the test by considering the near-field coupling between two nanowires. Compared with a conventional Yee-based approach, the proposed ADHIE-TDDFT method demonstrates similar accuracy, while reducing the computation time by more than a factor of five.