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Strain-induced electronic phase transition and strong enhancement of thermopower of TiS2

Samanta, Atanu and Pandey, Tribhuwan and Singh, Abhishek K (2014) Strain-induced electronic phase transition and strong enhancement of thermopower of TiS2. In: PHYSICAL REVIEW B, 90 (17).

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Official URL: http://dx.doi.org/ 10.1103/PhysRevB.90.174301


Using first-principles density functional theory calculations, we show a semimetal to semiconducting electronic phase transition for bulk TiS2 by applying uniform biaxial tensile strain. This electronic phase transition is triggered by charge transfer from Ti to S, which eventually reduces the overlap between Ti-(d) and S-(p) orbitals. The electronic transport calculations show a large anisotropy in electrical conductivity and thermopower, which is due to the difference in the effective masses along the in-plane and out-of-plane directions. Strain-induced opening of band gap together with changes in dispersion of bands lead to threefold enhancement in thermopower for both p-and n-type TiS2. We further demonstrate that the uniform tensile strain, which enhances the thermoelectric performance, can be achieved by doping TiS2 with larger iso-electronic elements such as Zr or Hf at Ti sites.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to the AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 29 Dec 2014 04:56
Last Modified: 29 Dec 2014 04:56
URI: http://eprints.iisc.ac.in/id/eprint/50527

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