Exchange and correlation energy functionals for two-dimensional open-shell systems

• Published in: Physica. E, Low-dimensional systems & nanostructures Low-dimensional systems & nanostructures, 2010-02, Vol.42 (4), p.1232-1235
• Main Authors: Räsänen, E., Pittalis, S.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Density-functional theory; Electron gas; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Quantum dot; Quantum dots
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2009.11.128

We consider density functionals for exchange and correlation energies in two-dimensional systems. The functionals are constructed by making use of exact constraints for the angular averages of the corresponding exchange and correlation holes, respectively, and assuming proportionality between their characteristic sizes. The electron current and spin are explicitly taken into account, so that the resulting functionals are suitable to deal with systems exhibiting orbital currents and/or spin polarization. Our numerical results show that in finite systems the proposed functionals outperform the standard two-dimensional local spin-density approximation, still performing well also in the important limit of the homogeneous two-dimensional electron gas.