Towards a predictive route for selection of doping elements for the thermoelectric compound PbTe from first-principles

Abstract

Striving for improvements of the thermoelectric (TE) properties of the technologically important lead telluride (PbTe) compound, we investigate the influence of different doping elements on the thermal conductivity, Seebeck coefficient, and electrical conductivity applying density functional theory calculations. Our approach combines total-energy calculations yielding lattice vibrational properties with the Boltzmann transport theory to obtain electronic transport properties. We find that doping with elements from the 1st and 3rd columns of the periodic table reduces the sound velocity and, consequently, the lattice thermal conductivity, while 2nd column dopants have no such influence. Furthermore, 1.6 at. % doping with 4th and 5th column elements provides the highest reduction of lattice thermal conductivity. Out of this group, Hf doping results in maximum reduction of the sound velocity from 2030 m s−1 for pure PbTe to 1370 m s−1, which is equivalent to ca. 32% reduction of lattice thermal conductivity. The highest power factor values calculated for 1.6 at. % doping range between 40 and 56 μW cm−1 K−2, and are obtained for substitution with dopants having the same valence as Pb or Te, such as those located at the 2nd, 14th, and 16th columns of the periodic table. We demonstrate how this method may be generalized for dopant-selection-oriented materials design aimed at improving TE performance of other compounds.

Structural stability of calcium-manganate based CaO(CaMnO3)m (m = 1, 2, 3, ∞) compounds for thermoelectric applications

“…Elastic constants, sound velocities, and Debye temperatures (θ D ) are calculated applying a 0.5 % strain on the unit cells and calculating their total energies employing force convergence criterion of 0.002 eVÅ -1 . This value of strain was optimized for all distorted unit cells in order to avoid breaking of lattice symmetry and to achieve the highest level of agreement with experimental data [30].…”

“…The exchangecorrelation energy is considered in the framework of generalized gradient approximation (GGA). We determine the elastic coefficients from the change of calculated total energies with respect to volumetric changes, depending on lattice symmetry [29,30].…”

Silver-Antimony-Telluride: From First-Principles Calculations to Thermoelectric Applications

“…Also, diference of electrical conductivity between La-doped and La-free materials is smaller for measured dataset than for calculated ones. This is probably due to diiculty to simulate low dopant concentrations in DFT [70]. Second, it is noteworthy that both values of electrical conductivity and Seebeck coeicients measured for La-free and La-doped materials converge at temperatures >650 K, Figure 9.…”

“…Finally, the explicit expression for Seebeck coeicient tensor, S ij , is given by [70,71]: Figure 1c and d, respectively. A computational routine similar to aforementioned one is implemented with several diferences.…”

“…SO coupling is often being considered in band structure calculations [32,70,75]. TE transport properties were calculated according to the procedure detailed by Eqs.…”