A Detailed Experimental and Theoretical Study of the Crystalline and Electronic Structure of BaHf(1−x)ZrxS3 Solid Solutions (0 ≤ x ≤ 1)

Solid solutions of the chalcogenide perovskites BaHfS3 and BaZrS3 are synthesized and studied in detail across the entire composition interval by X-ray diffraction, UV-vis spectroscopy, and theoretical calculations. The results obtained extend those previously obtained by the same authors in previous works, giving a deeper insight into the structure-electronic properties relationship of these materials. Furthermore, high-resolution synchrotron radiation powder X-ray diffraction data are obtained for pure BaHfS3 and BaZrS3. In particular, the analysis of a higher number of compositions reveals that the cell volume of the solid solutions decreases linearly with increasing Hf content, while the unit cell axes, though showing a decreasing behavior with increasing Hf content, do not show a well-defined trend. The bandgap values of the solid solutions show a more complex relationship with the composition and unit cell volume, that is, values of Hf/(Hf + Zr) ratio below 40% do not exert a significant influence on the bandgap value, which remains practically constant, and then it increases substantially up to reach the value for pure BaHfS3. The comparison of the experimental data with density functional theory calculations reveals a satisfactory agreement.