Electronic properties of transuranium compounds with HoCoGa-type tetragonal crystal structure

Maehira, Takahiro*; Hotta, Takashi; Ueda, Kazuo*; Hasegawa, Akira*

By using a relativistic band-structrue calculation method, we investigate energy band structures and the Fermi surfaces of NpTGa, PuTGa, and AmCoGa with transition metal atoms T. It is found in common that the energy bands in the vicinity of the Fermi level are mainly due to the large hybridization between and Ga electrons. For PuTGa, we observe several cylindrical sheets of Fermi surfaces with large volume for T=Co, Rh, and Ir. It is also found that the Fermi surfaces of NpFeGa, NpCoGa, and NpNiGa are similar to those of UCoGa, UNiGa, and PuCoGa, respectively, except for small details. For AmCoGa, the Fermi surfaces are found to consist of large cylindrical electron sheets and small closed hole sheets, similar to PuCoGa. The similarity is basically understood by a rigid-band picture.