<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><DIV>Dear all</DIV>
<DIV> I want to calculate the density of state of graphene but there is a problem that it is extremely variant by changing the parameters. the best plot of DOS that I could find is linear at fermi energy but there is a gap there. </DIV>
<DIV>what is the reason of these variation? and which parameters should be adjusted? would you give me an input which you know it gives a good resault. the potential that I use is in LDA approximation.</DIV>
<DIV> </DIV>
<DIV>thank you.</DIV>
<DIV> </DIV>
<DIV>M. Aghtar</DIV>
<DIV> </DIV>
<DIV>Msc student</DIV>
<DIV>physics department of Kashan university </DIV></div><br>
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