SYMMETRY PROPERTIES OF ELECTRONIC STATES OF CRYSTALS WITH SPIRAL MAGNETIC ORDER

It is shown that for spiral magnetic structures, both the condition imposed on the symmetry operations belonging to the group of a given Bloch vector and the formula describing the symmetry of the band structure differ essentially from the counterparts used in traditional cases of collinear and non-magnetic crystals. The character of the band structure symmetry is analysed for different types of symmetry operations. It is shown that contrary to the traditional cases, there are spiral structures whose band structure is described by nonsymmorphic space groups. A corresponding example is given. © 1990.