Dear Prof. Madsen, I am reading your paper "BoltzTrap. A code for ...." (Computer Physics Communications 175 (2006) 6771 ) And I wanna know how did you get the Fig.4? could you teach me a little more in detail? And How can I calculate the carrier concentration? Sorry to disturb you. Thank you very much! Best regards -------------- Long-Hua Li 2009-02-13