Fig. 3
From: Topological superconducting phase in high-Tc superconductor MgB2 with Dirac–nodal-line fermions
Effective model of dispersive DNL of MgB2 and Berry phase analysis. a The calculated band structure of an effective model (red lines) using B pz orbitals with parameters t = 1.50 eV and tz = 0.954 eV with DFT band structure. b The pseudospin texture with the corresponding valence energies. The arrows represent the pseudospin. The color gradient from red to blue represents energies of valence states. The blue and red dashed circles correspond to the electron and hole extremum orbits in a magnetic field (B) along the z direction at EF = 0 eV. The blue and red solid circle correspond to the electron and hole extremum orbits at EF = +1.0 eV. c The Fermi surfaces for EF = −1.2 eV, EF = 0 eV, and EF = +1.0 eV, respectively. The electron (hole) Fermi surfaces are indicated by blue (red) isosurfaces. The extremum orbits are indicated by a dashed line (solid line) for EF = 0 eV (EF = +1.0 eV)
