Electronic structure and optical properties of CuWO4: An ab initio study

Electronic structure and optical properties of copper tungstate CuWO4 were investigated using density functional theory with improved version of exchange potential suggested recently by Tran and Blaha (2009) [7] (TB-mBJ). The calculated band gap value is found to be in excellent agreement with the recent experimental results. The values of the magnetic moments at the Cu sites and O (3) oxygen atomic sites (closest to the Cu2+ ions in antiferromagnetic chains) are in good agreement with experiments also. The principal characteristic of the calculated electronic structure is significant rearrangement of the Cu 3d states near the valence band top as compared to our earlier PBE and PBE + U calculations of the same compound. This fact causes the different optical response of the CuWO4 as well, which is analyzed and interpreted in terms of calculated electronic structure. A comparison of the calculated properties with available experimental data indicates that the TB-mBJ approach provides a better description of the electronic and optical properties of the CuWO4 compound than the standard PBE and PBE + U approaches.