Identification of the neutral V4+ impurity in cubic 3C-SiC by electron-spin resonance and optically detected magnetic resonance

Nominally undoped zinc-blende polytype 3C-SiC single crystals have been studied by conventional electron-spin resonance (ESR), by the magnetic circular dichroism (MCD) absorption technique, and by optically detected ESR via the MCD (MCD-ESR). Apart from the dominant ESR signal ascribed to residual boron acceptors, an anisotropic spectrum with many fines is observed near liquid-He temperatures. It collapses into a hyperfine octet for H (111). This spectrum is identified as the anisotropic 2E ground-state resonance of V high4plus (3d high1) on the cubic Si site in 3C-SiC. Above 15 K this spectrum disappears and an isotropic hyperfine octet appears. It is interpreted as the motionally averaged spectrum of the anisotropic V high4plus spectrum. The data are analyzed in terms of Ham's theory of the dynamic Jahn-Teller effect for a high2 E state. A sharp optical line at 6681 cm high-1 has been found in MCD absorption. On this line the MCD-ESR of V high4plus is observed, which identifies the l ine as being related to V high4plus. It is interpreted as the zero-phonon line of the V high4plus high2 E about high2 T sub2 crystal-field transition.