Dear Reza,
In addition to what Lorenzo suggested in relation to the accuracy of DFT in describing the band gap, there is a possibility that point defects can play a role in reducing the gap as the temperature increases. You might need to inspect the literature more to see how the observed reduction in the band gap was explained for the material of interest. Regards, Mostafa MIT
_______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
