GAPLESS STATE IN CUFES2

A theoretical group analysis of the CuFeS2 structure is made in the presence of magnetic order. It is shown that in such a structure a gapless state may obtained at a point P of the Brillouin zone of chalcopyrite. The existence of ferron states is pointed out. A construction is made of a ferron state corresponding to the specified irreducible representation of the wave vector group of point P of the Brillouin zone. As a result of the analysis the conclusion is made that CuFeS2 refers to gapless magnetic semiconductors where the gapless state is materialized at the boundary of the Brillouin zone and corresponds to a special case of spatial symmetry. In addition, the gapless state appears to be implemented not in usual but in ferron bands. The existence of a ferron hole is predicted. It is pointed out that the gapless state in CuFeS2 corresponds to the first type gapless state according to the character of the temperature dependence of concentration. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA