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Title: High temperature thermoelectric properties of Zr and Hf based transition metal dichalcogenides: A first principles study

Abstract

We investigate the electronic and thermal transport properties of bulk MX{sub 2} compounds (M = Zr, Hf and X = S, Se) by first-principles calculations and semi-classical Boltzmann transport theory. The band structure shows the confinement of heavy and light bands along the out of plane and in-plane directions, respectively. This results in high electrical conductivity (σ) and large thermopower leading to a high power factor (S{sup 2}σ) for moderate n-type doping. The phonon dispersion demonstrates low frequency flat acoustical modes, which results in low group velocities (v{sub g}). Consequently, lowering the lattice thermal conductivity (κ{sub latt}) below 2 W/m K. Low κ{sub latt} combined with high power factor results in ZT > 0.8 for all the bulk MX{sub 2} compounds at high temperature of 1200 K. In particular, the ZT{sub max} of HfSe{sub 2} exceeds 1 at 1400 K. Our results show that Hf/Zr based dichalcogenides are very promising for high temperature thermoelectric application.

Authors:
;
Publication Date:
OSTI Identifier:
22493353
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 143; Journal Issue: 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL LATTICES; ELECTRIC CONDUCTIVITY; HAFNIUM SELENIDES; HAFNIUM SULFIDES; PHONONS; THERMAL CONDUCTIVITY; THERMOELECTRIC PROPERTIES; TRANSPORT THEORY; VISIBLE RADIATION; ZIRCONIUM SELENIDES; ZIRCONIUM SULFIDES

Citation Formats

Yumnam, George, Pandey, Tribhuwan, and Singh, Abhishek K., E-mail: abhishek@mrc.iisc.ernet.in. High temperature thermoelectric properties of Zr and Hf based transition metal dichalcogenides: A first principles study. United States: N. p., 2015. Web. doi:10.1063/1.4937774.
Yumnam, George, Pandey, Tribhuwan, & Singh, Abhishek K., E-mail: abhishek@mrc.iisc.ernet.in. High temperature thermoelectric properties of Zr and Hf based transition metal dichalcogenides: A first principles study. United States. https://doi.org/10.1063/1.4937774
Yumnam, George, Pandey, Tribhuwan, and Singh, Abhishek K., E-mail: abhishek@mrc.iisc.ernet.in. 2015. "High temperature thermoelectric properties of Zr and Hf based transition metal dichalcogenides: A first principles study". United States. https://doi.org/10.1063/1.4937774.
@article{osti_22493353,
title = {High temperature thermoelectric properties of Zr and Hf based transition metal dichalcogenides: A first principles study},
author = {Yumnam, George and Pandey, Tribhuwan and Singh, Abhishek K., E-mail: abhishek@mrc.iisc.ernet.in},
abstractNote = {We investigate the electronic and thermal transport properties of bulk MX{sub 2} compounds (M = Zr, Hf and X = S, Se) by first-principles calculations and semi-classical Boltzmann transport theory. The band structure shows the confinement of heavy and light bands along the out of plane and in-plane directions, respectively. This results in high electrical conductivity (σ) and large thermopower leading to a high power factor (S{sup 2}σ) for moderate n-type doping. The phonon dispersion demonstrates low frequency flat acoustical modes, which results in low group velocities (v{sub g}). Consequently, lowering the lattice thermal conductivity (κ{sub latt}) below 2 W/m K. Low κ{sub latt} combined with high power factor results in ZT > 0.8 for all the bulk MX{sub 2} compounds at high temperature of 1200 K. In particular, the ZT{sub max} of HfSe{sub 2} exceeds 1 at 1400 K. Our results show that Hf/Zr based dichalcogenides are very promising for high temperature thermoelectric application.},
doi = {10.1063/1.4937774},
url = {https://www.osti.gov/biblio/22493353}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 23,
volume = 143,
place = {United States},
year = {Mon Dec 21 00:00:00 EST 2015},
month = {Mon Dec 21 00:00:00 EST 2015}
}