Fig. 3: Localization of electronic states near the Fermi level on domain walls.
a Electronic band structure of GeTe containing 39° (11\(\bar{1}\)) tail-to-tail (T-T) and head-to-head (H-H) domain walls (DWs) projected on the DW plane. The eigenvalues of the states with the reciprocal lattice vector normal to the DW plane (k3) set to zero are shown in blue, while the dispersion of these states as k3 changes is shown in red. The grey area in the graph corresponds to the bulk GeTe band structure projected to the domain wall plane. The horizontal line represents the Fermi level at 0 K. The absence of dispersion for the states near the Fermi level confirms their localization due to electric fields along domains. The side plot shows the local density of states of the T-T DW. b Charge density associated with the states labelled as 1. and 2. in a, as a function of the coordinate normal to the DWs, which are indicated by black vertical lines. These states are clearly localized on the DWs.
