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Simple Criterion for Wurtzite-Zinc-Blende Polytypism in Semiconductors

The relative stability between wurtzite and zinc-blende structures in semiconductors is systematically investigated using a simple formula for calculating the energy difference between them. Using the well-known values of ionicity and lattice parameter for semiconductors, the energy formula gives good estimates of the energy difference for group IV, III–V and II–VI semiconductors. The calculated energy differences for 16 semiconductors agree well with those obtained by ab initio calculations in the literature. A simple criterion for wurtzite-zinc-blende polytypes in semiconductors is extracted in terms of ionicity from the formula. The criterion implies that the wurtzite structure is stabler than the zinc blende structure when the ionicity is greater than 0.319 for group IV, 0.455 for III–V and 0.652 for II–VI semiconductors.