Quantum confinement effect on the vacancy-induced spin polarization in carbon, silicon, and germanium nanoparticles: Density functional analysis

Abstract

Density functional calculations were carried out to examine the vacancy-induced spin polarization in diamond, silicon, and germanium nanoparticles and the magnetic coupling between the vacancy-induced defect states in those nanoparticles. Our calculations show that the vacancy-induced defect states are spin-polarized in diamond nanoparticles regardless of their size but this happens in silicon and germanium nanoparticles only when their size is small, which is in reasonable agreement with the experimentally observed magnetic behaviors. The vacancy-induced defect states on adjacent vacancies prefer to couple ferromagnetically in C nanoparticles but antiferromagnetically in Si and Ge nanoparticles.