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
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