Calculated partial density of states (PDOS) of the 3d TM atom and its nearest-neighbor C atom for each substitutional doped DNT: (a) Sc-DNT, (b) Ti-DNT, (c) V-DNT, (d) Cr-DNT, (e) Mn-DNT, (f) Fe-DNT, (g) Co-DNT, (h) Ni-DNT. The FL is set to zero energy and indicated by the vertical green dashed line.