Structural instabilities in ternary semiconductors: the α → β transition of Cdln2 Se4

We report on a first-principle theoretical study of the structural properties of the α and β phases of the ternary semiconductor CdIn2 Se4. We have also studied the properties of two intermediate phases in a possible transition process α → β. Besides a good agreement with the experiment our overall result is that all these phases have so similar structural properties that in most of the cases the consideration of the simplest phase from the crystallographic point of view should be quite enough, with substantial savings in computer time. This result should also hold for the other members of the AB2C4 semiconductor family with D2d1 space group symmetry and should allow for an easier systematic investigation of their physical properties.