Thermal expansion of CuInTe2 from 30 to 300 K

The thermal expansion coefficients α/sub a/ and α/sub c/ of the lattice parameters a and c of CuInTe2 are measured in the temperature range from 30 to 300 K using the X-ray Bond method. Both α/sub a/ and α/sub c/ decrease with decreasing temperature and become negative at about 38 and 54 K, respectively. The results are discussed in terms of the principal Grueneisen parameters of chalcopyrite structure crystals. It is concluded that there are low-energy lattice vibrational modes with negative Grueneisen parameters in CuInTe2. A comparison is made with previous measurements for CuInTe2 and other Cu-III-VI2 compounds as well as with theoretical estimates. (author)