Non-vanishing Berry phase in chiral insulators
1 Institut für Festkörperphysik, Technische Universität Darmstadt - D-64289 Darmstadt, Germany
2 Max Planck Institute for Chemical Physics of Solids - D-01187 Dresden, Germany
Received: 13 November 2013
Accepted: 13 November 2013
The binary compounds FeSi, RuSi, and OsSi are chiral insulators crystallizing in the space group P213 which is cubic. By means of ab initio calculations we find for these compounds a non-vanishing electronic Berry phase, the sign of which depends on the handedness of the crystal. There is thus the possibility that the Berry phase signals the existence of a macroscopic electric polarization due to the electrons. We show that this is indeed so if a small external magnetic field is applied in the  direction. The electric polarization is oscillatory in the magnetic field and possesses a signature that distinguishes the handedness of the crystal. Our findings add to the discussion of topological classifications of insulators and are significant for spintronics applications, and in particular, for a deeper understanding of skyrmions in insulators.
PACS: 03.65.Vf – Phases: geometric; dynamic or topological / 71.20.Nr – Semiconductor compounds / 77.22.Ej – Polarization and depolarization
© EPLA, 2013