Microhardness, Debye temperature and bond ionicity of ternary chalcopyrite compounds

By analyzing the published data for the microhardness H of the A(II)B(IV)C(2)(V) and A(I)B(III)C(2)(VI) chalcopyrite-structure semiconductors, a linear relation between this parameter and its corresponding Debye temperature is found. On the basis of this result and taking into account that H for these compounds depends on the intrinsic defect equilibrium of the crystals, the microhardness of nearly stoichiometric samples is estimated. It is also found that H decreases as the ionicity increases and tends to vanish at f(i0)*approximate to 0.79. This is the critical ionicity that separates the four-fold chalcopyrite compounds with those of the six-fold structures.