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In the Dirac nodal line system, the Dirac points of the two dimensional Dirac cones draw lines in the three dimensional Brillouin zone. The Dirac nodal line system attracts the scientists due to the property such as the anomalous transport phenomena and topology. The first-principles calculation and the experiment show that the single-component molecular conductor [Pt(dmdt)₂] is the Dirac nodal line system.
We made the tight-binding model of [Pt(dmdt)₂] based on the first-principles calculation to investigate the electrical properties. It is predicted that [Pt(dmdt)₂] has topological property. Therefore, we calculated the edge state, using the tight-binding model. And, we found that the edge state whose flat energy dispersion between Dirac nodal lines appears [T. Kawamura, et al., J. Phys. Soc. Jpn. 89, 074704 (2020)]. Consequently, the Fermi surface at the edge has the good nesting vector due to the Dirac nodal line and the flat energy dispersion. It suggests that the nesting vector induces the edge magnetism. Therefore, we calculate the spin susceptibility using real spatial RPA of the Hubbard model and discuss the edge magnetism. In addition, we discuss the possibility that carrier doping controls the magnetic structure at the edge.