[Wien] Temperature

[Fecher, Gerhard]

Dear Brik,
What do you mean with "I know there is no semiconductor at 0 kelvin" ?

In general, every semiconductor is an insulator, that is, these are materials with a band gap just above the Fermi energy (highest occuoied state at 0K).
The size of the band gap is used to distinguish semiconductors (small gap) and insulators (large gap). However, the terms "small" and "large" are fuzzy and one cannot give just one value that defines a border.

At elevated temperatures electrons are excited into the conduction band and the material  is able to carry a (small) electric current that depends exponetially on Temperature and band gap.
The larger the band gap the higher the temperature needed to detect that current. 

Depending on some strange point of views you could also say "I know that all metals are at Zero temperature either insulators or superconductors or both at once",
but I don't think that this is a good idea.

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Physics
Johannes Gutenberg - University
55099 Mainz
________________________________________
Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Brik Hamida [hmd.brik at gmail.com]
Gesendet: Montag, 4. Juli 2022 19:09
An: wien-request at zeus.theochem.tuwien.ac.at
Cc: wien at zeus.theochem.tuwien.ac.at
Betreff: [Wien] Temperature

Dear users

With Wien2k  I was calculated the band structure of one material which is a semiconductor . The DFT calculations in wien2k are carried at T=0 kelvin. AS  I know there is no semiconductor at 0 kelvin. So How we can explain the semiconductor nature at 0 kelvin with dft calculation ?

Best regards