DIRECT OBSERVATION OF A LATTICE INSTABILITY IN HEAVILY IN-DOPED CDTE

The nearest-neighbor environment around Cd atoms in CdTe and CdTe dope d with 5 and 8 at. % indium was determined from Cd K-edge x-ray-absorp tion fine-structure measurements. The first shell of neighbors is spli t into two distances R(1) = 2.58 +/- 0.02 Angstrom, and R(2) = 2.81 +/ - 0.01 Angstrom, for the doped samples. The presence of the short dist ance R(1) = 2.58 Angstrom is related to the existence of lattice relax ations produced by the introduction of indium.