# [Pw_forum] Local density of electronic entropy

Paolo Giannozzi giannozz at nest.sns.it
Tue Dec 11 22:42:55 CET 2007

On Dec 10, 2007, at 11:52 , Clark Lee wrote:

> I am very appreciated getting some literature or theoretical
> background
> about 'local density of electronic entropy'.

I am not aware of any specific reference and don't know what the
code that calculates it actually does; my guess is that it is the
entropy
of a Fermi-Dirac gas, f log(f) + (1-f)log(1-f), where f is the occupancy
(can be found in textbooks), weighted with the local density of states
at the Fermi energy: \sum_i |\psi_i(r)|^2 \delta(E_F-e_i)

P.
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Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222