(a) Energy variation and kinetic barrier for CH₂OCH₃ rotations in functionalized arsenene; the insets show the structural models. (b) Variation of the polarization along the x and y directions. (c) Electronic band structures of the symmetric ligand configuration with the rotation angle of 0° (left) and the the asymmetric ligand configuration with the rotation angle of 120° (right). The topological order is preserved under the ligand rotation, although there is a band splitting due to an out-of-plane symmetry breaking.^[113]