FP-PLAW study of structural and electronic properties of Tin oxides

L. A. ERRICO

La Plata, Bs As, Argentina

Workshop; 35th anniversary of Hyperfine Interactions at La Plata International Workshop; 2005

-

Two tin oxide compounds, SnO and SnO2, are known to crystallize under ambient conditions. Tin oxides films are of particular importance due to its applications in solar cells, gas-sensing element sensors, and electronic components. For these reasons, several theoretical and experimental studies have intensively developed (see, e.g., refs. [1-4] and refs. therein). Very recently, the interest in SnO2 was renewed due to the discovery of high-temperature ferromagnetism in Sn1-xCoxO2-d films [5]. In order to study within an ab initio framework the effect of impurities in SnO and SnO2 and to simulate the films it is essential to determine first the structural and electronic properties of the bulk material, in order to discriminate between effect induced by the impurity or the films surfaces and those originated in the host material. In the present work we study the electronic structure of pure bulk SnO and SnO2 based on first-principles solid-state calculations, using the Full-Potential Linearized-Augmented-Plane-Waves (FP-LAPW) method. In particular, we focused our attention on the determination of the internal atomic coordinates and the dependence of the electronic properties on them. The internal coordinates were determined by force minimization. The obtained  results are in excellent agreement with those obtained by x-ray diffraction [6, 7] and LMTO [4] calculations reported in the literature. Using these parameters we determined the electric-field gradient (EFG) tensor. The results for the EFG tensor are compared with those obtained in Mössbauer experiments [2] and in cluster calculations [3].