Spin state of vacancies from magnetic Jahn-Teller distortions to multiplets

ae spin configuration of isoelectronic vacancies surrounded by first-row at oms is studied within density functional theory (DFT) using the local spin density approximation. Allowing for a symmetry break in the electronic syst em, a mixed-spin state is found to br lowest in energy. It is accompanied b y a magnetization density with reduced symmetry indicating a magnetic Jahn- Teller effect. The DFT results are discussed in terms of many-body wave fun ctions of a quantum-chemical treatment. Examples considered are neutral vac ancies in diamond and cubic SiG.