An efficient method for calculating spatially extended electronic states of large systems with a divide-and-conquer approach

摘要

We present an efficient post-processing method for calculating the electronicstructure of nanosystems based on the divide-and-conquer approach to densityfunctional theory (DC-DFT), in which a system is divided into subsystems whoseelectronic structure is solved separately. In this post process, the Kohn-ShamHamiltonian of the total system is easily derived from the orbitals and orbitalenergies of subsystems obtained by DC-DFT without time-consuming and redundantcomputation. The resultant orbitals spatially extended over the total systemare described as linear combinations of the orbitals of the subsystems. Thesize of the Hamiltonian matrix can be much reduced from that for conventionalcalculation, so that our method is fast and applicable to general huge systemsfor investigating the nature of electronic states.