Enhancement of thermoelectric efficiency of THfSe2 via nanostructuring

E. Unsal, R. T. Senger, and H. Sevinçli
Phys. Rev. B 103, 014104 – Published 11 January 2021

Abstract

In this work, ab initio calculations based on density functional theory and the Landauer formalism are carried out to investigate ballistic thermoelectric properties of THfSe2 nanoribbons (NRs). The zigzag-edged NRs are metallic, and they are not included in this study. The armchair NRs possess two types of edge symmetries depending on the number of atoms present in a row; odd-numbered NRs have mirror symmetry, whereas the even-numbered NRs have glide reflection symmetry. The armchair-edged NRs are dynamically stable and show semiconducting properties with varying band gap values in the infrared and visible regions. Detailed transport analyses show that the n-type Seebeck coefficient and the power factor differ because of the structural symmetry, whereas the p-type thermoelectric coefficients are not significantly influenced. It is shown that the phonon thermal conductance is reduced to a third of its two-dimensional value via nanostructuring. The p-type Seebeck coefficient and the power factor for T-phase HfSe2 are enhanced in NRs. We report that the p-type ZT value of HfSe2 NRs at 300 and 800 K are enhanced by factors of 4 and 3, respectively.

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  • Received 5 June 2020
  • Revised 27 October 2020
  • Accepted 8 December 2020

DOI:https://doi.org/10.1103/PhysRevB.103.014104

©2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

E. Unsal1,2, R. T. Senger1,3, and H. Sevinçli2,*

  • 1Department of Physics, Izmir Institute of Technology, 35430 Izmir, Turkey
  • 2Department of Materials Science and Engineering, Izmir Institute of Technology, 35430 Izmir, Turkey
  • 3Department of Physics, University of California, Davis, California 95616, USA

  • *haldunsevincli@iyte.edu.tr

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Vol. 103, Iss. 1 — 1 January 2021

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