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

Abstract

Since they have become indispensable in various technological applications and a powerfulsource for generating energy in thermoelectric devices, Lithium-based alloys symbolize the topicof many experimental and theoretical reports. Hence, LiAlX(X = C, Si, Ge, Sn) materials representthe main research in this study. Different interesting properties such as the effect of pressure onthe band gap as well as the elastic parameters and the thermoelectric efficiency of these materialswere 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 themechanical properties, we found that LiAlC alloy is stable against a wide range of pressurechanges (90 GPa), while the rest three systems preserve their mechanical stability in a moderaterespectively range of 40, 50 and 30 GPa, respectively. The semiconducting band gap for eachpossible transition have been calculated in a range of different pressures using both GGA andmBJ-GGA approximations. The results ended up revealing a decaying trend of the indirect gapalong Г-X direction with the increase of pressure. High values of the power factor were achievedand a large figure of merit (almost 0.7 for all systems) was calculated at 600K, which makesthese Li-based alloys very auspicious in the thermoelectric field applications.

An overview of commercialization and marketization of thermoelectric generators for low-temperature waste heat recovery

“…In contrast, PbTe, GeTe, and SiGe are the mainstream development material in medium- and high-temperature ranges.

Figure 3 Materials’ temperature-dependence ZT values Temperature dependence of ZT for (A) N-type thermoelectric materials of (GeTe) 0.45 (AgBiTe 2 ) 0.55 , 38 (Ge 0.6 Pb 0.4 ) 0.88 Bi 0.12 Te 0.6 Se 0.4 , 38 (GeTe) 50 (AgBiSe 2 ) 50 , 38 CuInTe 2 , 39 MgSb, 40 InMn, 41 Ag 2 Se, 42 Pb 1.075 Se 0.8 Te 0.2 , 43 Bi 1.8 Zn 0.2 Te 3 , 44 Bi 2 Ge 1.45 Te 4 , 45 and Pb 0.98 Ga 0.02 Te 46 and (B) P-type thermoelectric materials of GeTe, 38 Ge 0.82 Pb 0.1 Bi 0.04 Mn 0.04 Te, 38 Ge 0.86 Ti 0.03 Sb 0.08 Te, 38 (GeTe) 0.8 (AgBiTe 2 ) 0.2 , 38 LiAlSn, 47 Ba 2 AuBi, 48 RbK 2 Sb, 49 Pb 0.973 Na 0.02 Ge 0.007 Te, 46 Pb 0.95 Na 0.05 Te-0.5% AgInSe 2 , 50 Ge 0.95 Bi 0.05 Te 0.7 Se 0.3 , 51 Ge 0.82 Pb 0.1 Bi 0.04 Mn 0.04 Te, 52 and SnTe0.15%MnTe0.2%Bi. 53

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