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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Dear PWSCF,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I plan to calculate the impurity binding energy of P-doped
Si bulk. I searched literatures, and I see people used mainly Effective
mass approximation (EMA) (or used first principles to obtain potential,
then used EMA). According these papers, the binding energy is determined
as the difference between impurity level and the minimum of the conduction
band. I also found other papers by Chelikowsky et al (Nano Letters 8, 596
(2008), PRL 92, 46802 (2004)), who calculated binding energy of P-doped
nanocrytals by calculating the ionization energy, I_d, of SiP system with one
electron removed, and the affinity, A_p, of the pure Si system with one
electron added. The binding energy is determined as:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>E_b = I_d – A_p<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I saw problems when I want to calculate E_b by Chelikowski’s
method, since that method only works for non-extensive system such as
nanocrystals. For P-doped Si bulk (with periodic boundary condtion), I
cannot calculate I_d and A_p (or there may be a way that I do not know). If
using DFT, I do not know (using espresso code) how I define the binding energy
properly. Is the definition of binding energy as used in EMA is still
valid? <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I appreciate very much if you know an alternative to
calculate binding energy by using DFT. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thank you,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Trinh<o:p></o:p></span></font></p>
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