Figure 3 | NPG Asia Materials

Figure 3

From: Quantum spin Hall insulators and quantum valley Hall insulators of BiX/SbX (X=H, F, Cl and Br) monolayers with a record bulk band gap

Figure 3

Band structures of the BiX monolayers without (gray) and with (red) the SOC and Z2 topological invariant: (a) BiH, (b) BiF and (c) SbF monolayers. The Fermi level is set to zero. The bands near the Fermi level consist of the px and py orbitals. The size of the symbols is proportional to the population of the px and py orbitals. (d) n-field configuration for BiH monolayer. The calculated torus in the Brillouin zone is spanned by G1 and G2. Note that the two reciprocal lattice vectors form an angle of 120°. The white and black circles represent n=1 and −1, respectively, while the blank represents 0. The Z2 invariant is 1, obtained by summing the n-field over half of the torus mod 2.

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