THEORETICAL STUDY OF THE STRUCTURAL, ELECTRONIC AND VIBRATIONAL PROPERTIES OF CdIn_{2}Te_{4}

Miguel Fuentes-Cabrera, and Otto F. Sankey. Department of Physics and Astronomy and Materials Research Center, Arizona State University, Tempe, Arizona 85287.

The ternary ordered-vacancy semiconductor compound CdIn_{2}Te_{4} experimentally has

two structural types, one the I2 m space group and the other I2 By means of a planewave pseudopotential local density approximation we have optimized the structural parameters of these two polymorphs, where we have considered each one of them to have an ordered distribution of cadmium and indium atoms. The electronic and vibrational properties have been then investigated. We conclude that the I structure is negligibly more stable than the I2 m structure (Riede *et* al.[1] have found the I2 m to be the most stable candidate). We report equations of state for these structures, and other high pressure phases. Both I2 m and I structures have a direct band gap within the LDA at the Gamma point: 0.5eV for the I2 m

(Santana-Aranda et al. [2] reported a direct band gap ranging from 1.1 to 1.2eV) and 0.75 eV for I. We will discuss our results and compare them to experiment, including the vibrational Raman modes.

[1] H. Hahn, G. Frank, W. Klinger, A.N. Störger and G. Störger,

Z. Anorg. Allg. Chem., **279**, 241, (1955).

[1] V. Riede, H. Neumann, V. Krämer, and M. Kittel, Solid State

Commun. **78**, 211 (1991).

[3] J-C. Launay, J-F. Lambert, B. Darriet, and P. Gravereau,

J. Mater. Chem., **5,** 165, (1995).

[2] M.A. Santana-Aranda, J. Luyo-Alvarado, M. Mélendez-Lira,

M. Zapata-Torres, A. Zapata-Navarro, S. Jiménez-Sandoval,

R. Castro-Rodríguez, J.L. Peña, Superficies y Vacio **8**,

69-73 (1999).

pacs{63.20-e, 71.15.Mb, 71.20.Mq}