[Wien] Ionized impurity centers in semiconductors

[Kamil Klier]

Dear Colleagues.

Kindly advise on how to handle ionized impurities in semiconductors.   
An example is Boron-doped Silicon. The neutral supercell of Si  
contains a small concentration of substitutional B acceptor, which is  
not ionized at T=0. Upon excitation, B acquires negative charge which  
creates a hole in the valence band, so that the cell is still neutral.

Instructions in:

http://www.wien2k.at/reg_user/faq/charged_cells.html

refer, however, to a charged cell.  Therefore, this case may not be  
relevant to the above B/Si case - is this correct?

The question therefore is how to handle the negative charge on B and  
the hole in the VB (preferably at VBM): add an electron in case.in2c,  
and create a hole in case.inm by choosing occupancy -1.0 ?

Or somehow selecting a small energy range at VBM and force zero  
occupancy in it?

Regards,

Kamil Klier
Lehigh University

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