Self-interaction-corrected local density approximation pseudopotential calculations of the structural phase transformations of ZnO and ZnS under highpressure

The structural phase transformations under high pressure of ZnO and ZnS hav e been investigated by using the Vogel-Kruger-Pollmann (VKP) scheme, in whi ch the electronic self-interaction correction to the local density approxim ation (LDA) is introduced in a non-self-consistent manner within the pseudo potential approach. In these calculations, I have used highly optimized pse udopotentials and a plane-wave expansion of the wavefunctions. Moreover, th e electronic structures of the zinc-blende (ZB) and rock-salt (RS) phases o f both compounds have been similarly calculated. It has been found that the VKP scheme provides a highly improved description, relative to the LDA res ults, for the structural and electronic structure properties of the conside red systems. However, the so-calculated transition pressures of the ZB-to-R S transition for both ZnO and ZnS are found to be significantly larger than the experimental data. RS-ZnO is predicted to be an indirect-gap semicondu ctor, with a wide band gap of 4.2 eV.