Elastic constants, electronic properties and thermoelectric response of LiAlX (X=C, Si, Ge, And Sn) half-Heusler


  • ROZALE HABIB Condensed matter and sustainable development Laboratory MDD Department, Faculty of Science, University of Sidi-Bel-Abbes, Sidi-Bel-Abbes, 22000-Algeria
  • M. Khetir University of Sidi Bel- Abbes
  • A. Maafa University of Sidi Bel- Abbes
  • F. Boukabrime University of Sidi Bel- Abbes
  • A. Bouabça University of Sidi Bel- Abbes
  • A. Chahed University of Sidi Bel- Abbes




Lithium-based alloys, DFT, FPLAPW, Elastic constants, electronic properties, thermoelectric response


Since they have become indispensable in various technological applications and a powerful
source for generating energy in thermoelectric devices, Lithium-based alloys symbolize the topic
of many experimental and theoretical reports. Hence, LiAlX(X = C, Si, Ge, Sn) materials represent
the main research in this study. Different interesting properties such as the effect of pressure on
the band gap as well as the elastic parameters and the thermoelectric efficiency of these materials
were investigated using the full potential linearized augmented plane wave (FP-LAPW) method.
LiAlX alloys were found to be semiconducting with indirect band gaps. When studying the
mechanical properties, we found that LiAlC alloy is stable against a wide range of pressure
changes (90 GPa), while the rest three systems preserve their mechanical stability in a moderate
respectively range of 40, 50 and 30 GPa, respectively. The semiconducting band gap for each
possible transition have been calculated in a range of different pressures using both GGA and
mBJ-GGA approximations. The results ended up revealing a decaying trend of the indirect gap
along Г-X direction with the increase of pressure. High values of the power factor were achieved
and a large figure of merit (almost 0.7 for all systems) was calculated at 600K, which makes
these Li-based alloys very auspicious in the thermoelectric field applications.


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