[Wien] BoltzTrap-electronic thermal conductivity

[Gavin Abo]

Your understanding is correct.  The BoltzTraP code solves an 
approximation of the electronic Boltzmann transport equation that 
outputs electronic thermal conductivity per relaxation time (ke/τ).

On the other hand, the phonon Boltzmann transport equation for example 
has to be solved to get the lattice thermal conductivity (kl). almaBTE 
is a code for VASP [1] and phono3py is a code for Quantum Espresso (QE) 
[2]. Unfortunately, I have yet to find one that supports WIEN2k.

If you're referring to the unsupported user contributed 
add_boltz2_to_w2web that hasn't been maintained to work with the latest 
bug fixed [3] WIEN2k version, then that add_boltz2_to_w2web package did 
output an incorrect ZT value assuming kl =0 in its calculation.

For example, the LaFe3CoSb12 experimental zT value at 300 K is 0.14 in 
Table I of the paper titled "Seebeck Coefficient and the Thermoelectric 
Figure of Merit in Semiconductors and Conducting Polymers" by B. F. 
Howell et al at [4].

If kl is ignored, ZT is computed as 0.54 which is far from the 
experimental value of 0.14.

ZT ≈ σS^2T/ke = {6.3860e+04 1/(ohm*m)}*{1.0090e-04 V/K}^2*{300 K}/{0.36 
W/(K*m)} = 0.54

On the other hand, when kl is included, the computed value of 0.12 is 
close to the experimental value of 0.14.

ZT ≈ σS^2T/(ke + kl) = {6.3860e+04 1/(ohm*m)}*{1.0090e-04 V/K}^2*{300 
K}/{0.36 W/(K*m) + 1.26 W/(K*m) } = 0.12

[1] https://almabte.bitbucket.io/
[2] https://phonopy.github.io/phono3py/
[3] http://www.wien2k.at/reg_user/updates/
[4] Accession Number ADA327846 at: https://ntrl.ntis.gov/NTRL/

Kind Regards,

Gavin
WIEN2k user

On 2/15/2024 2:14 AM, Bara abujafar via Wien wrote:
> I would like to inquire about the BoltzTraP code implemented in the 
> WIEN2k package. I am uncertain whether it neglects lattice thermal 
> conductivity, as there are conflicting claims suggesting that 
> BoltzTrap may only focus on electronic thermal conductivity. Your 
> feedback on this matter would be greatly appreciated.
> With best regards
> Mohammed Abu-Jafar
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20240215/d64a114d/attachment.htm>