SELF-INTERACTION AND RELAXATION-CORRECTED PSEUDOPOTENTIALS FOR II-VI SEMICONDUCTORS

We report the construction of pseudopotentials that incorporate self-i nteraction corrections and electronic relaxation in an approximate but very efficient, physically well-founded, and mathematically well-defi ned way. These potentials are particularly useful for II-VI compounds which are distinguished by their highly localized and strongly bound c ationic semicore d electrons. Self-interaction corrections to the loca l-density approximation (LDA) of density-functional theory are account ed for in the solids to a significant degree by constructing appropria te self-interaction-corrected (SIC) pseudopotentials that take atomic SIC contributions into account. In this way translational symmetry of the Hamiltonian is preserved. Without increasing the complexity of the numerical calculations we approximately account, in addition, for ele ctronic relaxation in the solids by incorporating into our pseudopoten tials relevant relaxation in the involved atoms. By this construction we arrive at very useful self-interaction and relaxation-corrected pse udopotentials and effective one-particle Hamiltonians which constitute the basis for ab initio LDA calculations yielding significant improve ments in electronic properties of II-VI compound semiconductors and th eir surfaces. The procedure is computationally not more involved than any standard LDA calculation and, nevertheless, overcomes to a large e xtent the well-known shortcomings of ''state of the art'' LDA calculat ions employing standard pseudopotentials. Our results for electronic a nd structural properties of II-VI compounds agree with a whole body of experimental data.