paper

Modulation of electronic and thermal proprieties of TaMoS by controlling the repulsive interaction between Ta dopant atoms

arXiv:2108.03693 · doi:10.1016/j.ssc.2021.114590

Abstract

We theoretically study the electronic and the thermal characteristics of Tantalum, Ta, doped Molybdenum disulfide, MoS, using density functional theory. It has been shown that the MoS monolayer is not a good material for thermoelectric devices due to its relatively large band gap. We find that a Ta doped MoS forming a TaMoS monolayer can be useful for thermoelectric devices. The particular attention of this work is paid to the interaction effect between the Ta atoms in the MoS structure. We find that the interaction type is repulsive. It introduces an asymmetry in the density of states, DOS, reducing the band gap. In the presence of a strong repulsive interaction of Ta-Ta atoms, new states in the DOS around the Fermi energy are found leading to a reduction of the band gap. Consequently, a high Seebeck coefficient and figure of merit are seen over a wide range of energy around the Fermi energy. In contrast, a small reduction of the band gap and a vanishing degeneracy of the valence and the conduction bands are observed for the case of a weak Ta-Ta repulsive interaction leading to less promising thermoelectric properties.

7 pages, 7 figure

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