Ternary semiconducting compounds with chalcopyrite - type structure.
I fundamental equation and its physically acceptable solutions.
(Rodulfo de Gil, Eldrys)
Abstract

The equation (1/4) (c/a)2 = σ2 + 2ασ - 2, which relates all structural parameters for the ternary ABC2 semiconductors with chalcopyrite structure, is analyzed (c and a are the tetragonal lattice constants, σ = 4x =1, x = fractional coordinate of C atom, α = (d2AC + d2BC)/(d2AC - d2BC), dAC and dBC are the A-C and C-B bond distances respectively). The analysis gives the following results: 1. For 2.236 > (dBC/dAC) >0.447, a chalcopyrite-type structure is not possible. 2. For 0.447 < (dBC/dAC) < 0.557 or 1.732 < (dBC/dAC)< 2.236, (c/a) < 2 (tetragonal compression). 3. For (dBC/dAC) = 0.557 or 1.732 (c/a) ≤ 2. 4. For 0.557< (dBC/dAC) < 1.732, (c/a) ≥ 2. 5. For a given dBC/dAC the c/a values are between 0 and 2 (2|α| - 3)½ with |α|>1.5.