Hello Everyone,
As we know the Density functional theory deals at a 0 kelvin temperature and using the output of DFT scf calculations we can use the Boltztrap code to give us the thermoelectric properties at finite temperature.
So which factor is mainly responsible for that temperature part coming into play while calculating thermoelectric properties.
Is it only because of the temperature dependence of the Fermi distribution function in Boltzman equations?
I think when calculating the transport properties, the band structure is assumed to be temperature-independent. This should be a good assumption in most cases. The temperature dependence of the transport properties is then from the Fermi-Dirac statistical distribution and the temperature dependence of the scattering rate (relaxation time).
I consider that the validity of BOLTZTRAP is limited to systems where the rigid band scheme is valid. The energy change of Bloch states as the density of states tends to remain constant, with the Fermi surface remaining constant. The calculation of transport properties proceeds on this surface. The one that does not remain constant is the electrochemical potential that varies with temperature. In many highly dilute metals and alloys (usually not involving d-states), this approach works well. In the study of properties involving electrons, it is not easy to abstract from the physical mechanisms that define the property and its temperature dependence, acquiring the electron-phonon interaction increasingly important.
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