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A computational study of thermoelectric conversion in the PbSe$_{x}$Te$_{1-x}$ semiconductor alloys

M. Kaid Slimane, B. N. Brahmi, M. Bouchenaki, S. Bekhechi

TL;DR

This work employs FP-LAPW DFT with Wien2k and the GGA-PBE functional to predict the structural, electronic, and thermoelectric properties of PbTe, PbSe, and PbSe_xTe_1-x alloys. It finds Vegard-like variation of lattice parameters with Se content, nonlinear changes in the bulk modulus, and direct band gaps at the L-point across all compositions. Transport properties are computed via BoltzTrap2 and Gibbs2 over 120–1000 K, yielding Seebeck coefficients in the 100–320 microvolts per kelvin range and ZT values up to approximately 2.55, particularly for Se-rich compositions. The results highlight the strong thermoelectric potential of PbSe_xTe_1-x alloys and show how composition controls electronic structure and thermoelectric performance for high-temperature conversion applications.

Abstract

The present theoretical study focuses on the structural, electronic and thermoelectric properties of PbTe, PbSe and their ternary alloys PbSe$_{x}$Te$_{1-x}$, using the density functional theory (DFT) by the full potential linearised augmented plane wave (FP-LAPW) method implemented in Wien2k code. Structural properties were performed by using the generalized gradient approximation of Perdew Burke and Ernzenhof (GGA-PBE) scheme. The results show that the calculated lattice parameters are in good agreement with theoretical data previously obtained. For electronic properties, we noticed that for all the compounds of PbSe$_{x}$Te$_{1-x}$, we have a direct band gap in L point. For thermoelectric properties, we used BoltzTraP2 code and Gibbs2 code. Our results show that the PbSe$_{x}$Te$_{1-x}$ compounds have reached a value of 2.55 for the figure of merit, which indicates that our material is a good thermoelectric candidate.

A computational study of thermoelectric conversion in the PbSe$_{x}$Te$_{1-x}$ semiconductor alloys

TL;DR

This work employs FP-LAPW DFT with Wien2k and the GGA-PBE functional to predict the structural, electronic, and thermoelectric properties of PbTe, PbSe, and PbSe_xTe_1-x alloys. It finds Vegard-like variation of lattice parameters with Se content, nonlinear changes in the bulk modulus, and direct band gaps at the L-point across all compositions. Transport properties are computed via BoltzTrap2 and Gibbs2 over 120–1000 K, yielding Seebeck coefficients in the 100–320 microvolts per kelvin range and ZT values up to approximately 2.55, particularly for Se-rich compositions. The results highlight the strong thermoelectric potential of PbSe_xTe_1-x alloys and show how composition controls electronic structure and thermoelectric performance for high-temperature conversion applications.

Abstract

The present theoretical study focuses on the structural, electronic and thermoelectric properties of PbTe, PbSe and their ternary alloys PbSeTe, using the density functional theory (DFT) by the full potential linearised augmented plane wave (FP-LAPW) method implemented in Wien2k code. Structural properties were performed by using the generalized gradient approximation of Perdew Burke and Ernzenhof (GGA-PBE) scheme. The results show that the calculated lattice parameters are in good agreement with theoretical data previously obtained. For electronic properties, we noticed that for all the compounds of PbSeTe, we have a direct band gap in L point. For thermoelectric properties, we used BoltzTraP2 code and Gibbs2 code. Our results show that the PbSeTe compounds have reached a value of 2.55 for the figure of merit, which indicates that our material is a good thermoelectric candidate.

Paper Structure

This paper contains 11 sections, 7 equations, 7 figures, 3 tables.

Table of Contents

  1. Introduction
  2. Computational details
  3. Results and discussion
  4. Structural properties
  5. Electronic properties
  6. Thermoelectric properties
  7. Seebeck coefficient
  8. Electrical conductivity
  9. Thermal conductivity
  10. Figure of merit
  11. Conclusion

Figures (7)

  • Figure 1: (Colour online) Variation of (a) lattice parameter $a_0$ (b) bulk modulus $B$ versus concentration x of Se.
  • Figure 2: (Colour online) Composition dependence of the calculated band gap for PbSe$_{x}$Te$_{1-x}$.
  • Figure 3: (Colour online) Variation of Seebeck coefficient versus temperature for PbSe$_{x}$Te$_{1-x}$alloys.
  • Figure 4: (Colour online) Variation of electrical conductiviy versus temperature for PbSe$_{x}$Te$_{1-x}$alloys.
  • Figure 5: Variation of lattice conductivity $\kappa_l$ versus temperature.
  • ...and 2 more figures