Fig. 2From: Enhanced Confinement of Terahertz Surface Plasmon Polaritons in Bulk Dirac Semimetal-Insulator-Metal WaveguidesReal and imaginary parts of the effective refractive index neff for a, b different gap width g, where the Fermi energy of BDS is fixed to be EF = 70 meV, and c, d different values of the Fermi energy EF, where the gap width is fixed at g = 1 μmBack to article page