Role of f-electrons in Ca(La_1-xCe_x)₂S₄ (0 ≤ x ≤ 1) solid solutions: A DFT+U study

The main challenge in applications of rare-earth-based new materials is understanding the complexities that arise from the highly localized f-electrons that impact the properties of these materials significantly. We will present the first principles-based DFT+U study of structural, magnetic, electronic, and optical properties of Ca(La_1-x Ce_x)₂S₄ (0 ≤ x ≤ 1) solid solution. We employed a site-selection technique based on local magnetic moment to form Ce doped Ca(La_1-x Ce_x)₂S₄ solid solutions. The incorporation of f-electrons via Ce doping modifies properties of the parent compound, CaLa₂S₄. As the occupation of f-electron increases, magnetic phase transition, as well as semiconductor-to-metal transitions, have been observed. We will also explain the origin of the experimentally observed color in these solid solutions. Finally, we will emphasize the role of Ca in stabilizing these solid solutions. Our result agrees well with the available experimental results.