Molecular dynamics simulations of the lattice thermal conductivity of thermoelectric material CuInTe2

Abstract

The lattice thermal conductivity of thermoelectric material CuInTe 2 is predicted using classical molecular dynamics simulations, where a simple but effective Morse-type interatomic potential is constructed by fitting first-principles total energy calculations. In a broad temperature range from 300 to 900 K, our simulated results agree well with those measured experimentally, as well as those obtained from phonon Boltzmann transport equation. By introducing the Cd impurity and Cu vacancy, the thermal conductivity of CuInTe 2 can be effectively reduced to further enhance the thermoelectric performance of this chalcopyrite compound.Ternary I-III-VI chalcopyrite compounds (I=Cu, Ag, III= Al, Ga, In and VI=S, Se, Te) have been identified as good thermoelectric materials [1, 2, 3, 4] due to their lower thermal conductivity. Among them, the thermoelectric performance of CuInTe 2 compound [5, 6] has been widely reported. For the p-type CuInTe 2 , the efficiency of thermoelectric conversion, which is characterized by the so-called ZT, can reach 1.18 at 850 K [7]. The relatively larger ZT value of CuInTe 2 is due to the larger Seebeck coefficient ( S ) and moderate electrical conductivity (σ ). In order to further improve the thermoelectric performance of CuInTe 2 , many efforts have been devoted to optimize the power factor ( 2 S σ ). Alternatively, one can take some strategies to suppress the lattice thermal conductivity ( l κ ). It is worth noting that the thermal conductivity of CuInTe 2 at room temperature is relatively larger than those of

Capturing anharmonic and anisotropic natures in the thermotics and mechanics of Bi2Te3 thermoelectric material through an accurate and efficient potential

“…the Stillinger-Weber [85], Tersoff [86] or Huang potential for covalent materials) is necessary to describe the complex changes of crystal configuration that cannot neglect the lattice relaxation effects [73,87], such as the direction-limited behavior of covalent bonds, and there are several FF studies of telluride semiconductors [88][89][90][91] as examples listed in the supplementary material. In contrast, if the case is such that we pay less attention to this complex local lattice deformation, such as in thermal transport simulation, the more efficient two-body potentials are valid enough when the parameters accurately measure the relative strength of all the bonding, and have already been done for tellurides like CuInTe 2 [92], GeSbTe [93] and PbTe [94,95]. (PbTe also has a three-body potential [96].)…”

Chemical Composition Modulation Realizing Remarkable Improvement of Thermoelectric Performance in CuInTe2-Based Alloy

“…In this work, however, we propose a chemical composition modulation strategy trying to realize electro-acoustic coordination: , that is, alloying GeTe in CIT at first, aiming to gain degenerated or converged valence bands through improving its structural symmetry. − After that, we introduce a proper Cu deficiency (V Cu ) , to adjust the carrier concentration ( n H ) through unpinning the Fermi level ( F r ) in the madgap and, at the same time, suppress the phonon velocity and/or strengthen the structural anharmonicity through increasing lattice disorder. ,− By utilizing this strategy, we realize the electro-acoustic coordination effectively in the present material and improve the TE performance significantly with the highest ZT value of 1.51 at 838 K. This value ranks at a higher level among the CIT-based materials.…”

Size-dependent disproportionation (in ~ 2–20 nm regime) and hybrid Bond Valence derived interatomic potentials for BaTaO2N

“…On the other hand, two-body potentials are primarily applicable for ceramics which have a mixed bonding containing ionic and covalent character. In general, the interatomic potential for the covalent solids will be chosen as a combination of pair-wise interactions and interactions due to bond angle variation, e.g., Buckingham (Wei et al 2017) and Morse potentials (Xu et al 2015). For ionic solids, it will be a combination of electrostatic interaction and a repulsion term like the Born-Mayer potential (Jabraoui et al 2016).…”