Figure 4: Anisotropic Dirac bands in SrMnBi2 and CaMnBi2.
From: Interplay of Dirac electrons and magnetism in CaMnBi2 and SrMnBi2
(a,b) The dispersion of the Dirac bands (black lines) along the Γ–M direction of the Brilluion zone and the locus of the crossing point energy of the Dirac bands (magenta lines) without or with the SOC λSO for SrMnBi2. The lower and upper branches are shown in solid and dashed lines. The inset in b shows the isolated Dirac points (black dots D) in SrMnBi2 and continuous Dirac points (Dirac locus, magenta line) in CaMnBi2. (c,d) The corresponding Dirac bands (black lines) along the Γ–M direction and the Dirac locus (magenta lines) with the SOC λSO for CaMnBi2 at two different values of the exchange coupling JK. Here, the gap size between the lower and upper Dirac bands are dominated by the exchange coupling JK instead of the SOC λSO. Here, Δk=|k−kD|, where kD is the moment of the Dirac point. The Γ–M direction and Dirac locus direction are along the black line and magenta curve in the inset in b, respectively.
