BYIn recent years, there has been considerable interest in studying the various electronic properties of degenerate semiconductors because of their importance in device technology 11, 2/. Nevertheless, it appears from the literature that the contribution to the elastic constants of degenerate materials has been relatively less investigated 13, 41. It is well known that the carrier contribution to the elastic constants depends on the density-of-states function I31 . In semiconductors having parabolic energy band, e.g. n-Ge the Keyes theory exhibits an 8% lowering of the shear elastic constant C44 141. Therefore, in A Y B Z semiconductors having nonparabolic and non-standard energy bands the carrier contribution to the elastic constants will be rather significant due to the complicated variation of the density- In a strained semiconductor only the second-and the third-order elastic constants (hereafter referred to as C44 and C456) are affected 131. The carrier contribution to C44 and C456 can, respectively, be written as 141 and where a is the deformation-potential constant, E is the total energy of the carrier, N(E) is the density-of-states function, and fo is t h e Fermi-Dirac occupation probability factor. I t appears then that the evaluation of (1) and ( 2 ) requires an expression for N(E) which, in turn, is determined by the E-i; dispersion relation of ') Calcutta 700 032, India.