抄録
Electronic structures of TiO and NiO are investigated by the modified tightbinding approximation developed by Stern. The general character of the 3d–bands of TiO is found to be quite similar to that of Ni, or Cu. The total width of the 3d–bands is estimated as 6 ev. Thus, the width of the 3d–bands of TiO is nearly the same as that of Ni, or Cu. Since the band-width is fairly wide, the band approximation is expected to be applicable to TiO. The electrical conduction in TiO may be ascribed to the conduction in the d–bands. On the other hand, the total width of the 3d–bands of NiO is quite narrow. It is estimated as only 0.4 ev. However, the general character of the band is quite similar to that of TiO and the theory predicts that the NiO crystal is a conductor. Thus, we see that in the case of NiO there is a definite discrepancy between the simple band theory and the experiment.
