Zeeman spectroscopy of the vanadium luminescence in GaP and GaAs

A high-resolution study of the vanadium-induced A and B luminescence zero-phonon lines in GaP:V and GaAs:V is presented. The Zeeman splitting of line A (and that of B in GaAs) in fields up to 5.3 T has been investigated in detail. The analysis of the data strongly indicates that earlier assignments of lines A and B to ${\mathrm{V}}^{2+}$ (3$d^3$) must be revised and that the A,B lines must be assigned to the ${}_{}{}^3{}_{}{}^{}\mathrm{T}_2^{}{}_{}{}^{}$→${\mathrm{}}^3$ ${\mathrm{A}}_2$ crystal-field transition of ${\mathrm{V}}^{3+}$(3${\mathrm{d}}^2$). The A-B splittings in zero field can be well accounted for in terms of Ham’s theory of the dynamic Jahn-Teller effect. The strength of the vibronic coupling is found to be moderate, $E_{\mathrm{JT}/\mathrm{ħ}\mathrm{\omega }\mathrm{\approxeq }3.7}$, thus suggesting that a Jahn-Teller–induced static distortion does not occur. The dynamic Jahn-Teller model also provides a satisfactory description for the Zeeman splittings of lines A and B. Some very fine spectral details (<1 ${\mathrm{cm}}^{\mathrm{-}1}$), however, appear to be related to residual strains in the samples investigated.