The PDOS of related atoms were presented in Figure 2. where an obvious impurity state lacates at Fermi level. How can I give a reasonable explanation from the perspective of elecrons occupying the orbitals?
Besides that , the bader chareger of perfect and defect systems were also given in Fig.1.
comment:the host atoms(Si or C) considered in attached Figs were the nearest ones to H interstials.
there are four equivalent Si atoms as the first-neighbour atoms of H, here only one Si atom was considered
As far, as I understood, thequestion is to explain why the Si- and C-derived electronic states are present in the vicinity of the Fermi level of the doped system.
The explanation may vary depending on that what namely structutal polytype of SiC was considered. If we take that having the zinc blende structure, so from the general considerations the explanation may be the following.
The px,py,pz - states of carbon and silicon in highly symmetric znic blende structure are degenerate for all the atoms in the crystal, as a result the derived bands in perfect crystal are "orbitally" degenerate too.
Now, as we brnig the impurity in the crystal, 1) some pristine atoms may become to be placed in inequivalent positions with respect to defect; 2) the px,py,pz - states can be split by the low-symmetry fields of defects. As a result, the derived band also suffer the splitting, in this way some Si-p, C-p-derived states belonging initially to conductivity band of pristine system break away and shift towards the valence band. Finally, these states appear in the pristine band gap in the vicinity of the new position of Fermi level.
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