Effect of spin–orbit coupling on opto-electronic and magnetic properties of rare-earth terbium dioxide (TbO2): first principle calculationsArvind Kumar, Manish Kumar and Rishi P. SinghEur. Phys. J. Plus, 135 11 (2020) 939DOI: https://doi.org/10.1140/epjp/s13360-020-00901-y