Variety of spin polarization in the Gd-Sb compounds

Three Gd-Sb-based compounds, namely, GdSb₂, Gd₄Sb₃, GdSbS₂O, have been studied theoretically for electronic and band structure features for the first time. Strong electron correlations in the Gd 4f shell were accounted for in the GGA+U method. In our investigation, the variety of electronic properties was obtained from a metallic to a semiconducting one with an interesting half-metallic case in between. The calculations shown that GdSbS₂O is a narrow gap semiconductor, therefore, it has spin polarization at the Fermi energy equal to 0. Despite the layered crystal structure of GdSbS₂O, we obtained that van-der-Waals forces have negligible effect for its band structure. Another studied compound is GdSb₂, it is found to be metallic for both spin projections, the calculated value of spin-polarization here is 11.3%. This compound was also found to have an interesting topological feature in the band structure just below the Fermi energy which could be regarded as a Dirac point. The last considered compound, Gd₄Sb₃, was revealed to be a half-metal with the gap only in one spin projection with the value of 0.67 eV, for this reason, spin polarization in Gd₄Sb₃ is 100%. Thus, in our calculations we demonstrate that in the Gd-Sb compounds spin polarization at the Fermi energy can vary from 0 to 100% that makes this class of intermetallic compounds very interesting for functional applications. The results are published in Int. J. Mol. Sci. 24(10), 8778 (2023). This research was supported by Russian Science Foundation within project No. 22-42-02021.