I am studying Si nanowires with different cross sections. In my work, I plan to evaluate the thermoelectric performance variation between different configurations. To achieve this, my current approach is to evaluate the thermal conductivity of the nanowires using classical molecular dynamics simulations whereas the electrical properties are extracted through DFT calculations using SIESTA coupled with BoltzTraP2 (to solve the Boltzmann transport equation under the relaxation time approximation).
The drawback of this methodology is that BoltzTraP2 gives the the electrical conductivity of the structure per unit relaxation time. However, since I am interested in determining the relative variation of these properties between individual structures, I can still compare the
Seebeck coefficient and
electrical conductivity/ relaxation time and determine which structure is more suited for thermoelectric applications.
However, this whole comparison depends on whether the electron relaxation time remains constant between the individual configurations or not. Given that I use the same material (Si) and nanowires of similar diameters, would this assumption be reasonable?