Issue 29, 2021

The impact of electron–phonon coupling on the figure of merit of Nb2SiTe4 and Nb2GeTe4 ternary monolayers

Abstract

We have comprehensively demonstrated the thermal transport properties of Nb2SiTe4 and Nb2GeTe4 ternary monolayers by employing first-principles calculations and the semi-classical Boltzmann transport theory, including the electron–phonon coupling. The appealing features uncovered here for the monolayers are their colossal Seebeck coefficient and power factor at a higher carrier concentration. For example, the room temperature Seebeck coefficient lasts as high as 200 μV K−1 even at an increased hole (electron) concentration 6.32 × 1020 cm−3 (5.17 × 1019 cm−3) and 1.47 × 1020 cm−3 (5.18 × 1019 cm−3) for Nb2SiTe4 and Nb2GeTe4 monolayers, respectively. Our findings disclose similar band structures and moderate indirect bandgaps of 0.55 eV and 0.41 eV for Nb2SiTe4 and Nb2GeTe4 monolayers. The absence of imaginary frequencies in phonon band dispersion confirms the dynamic stability of both monolayers. The lowest value of lattice thermal conductivity turns out to be 14.30 W m−1 K−1 (12.30 W m−1 K−1) for Nb2SiTe4 and 11.70 W m−1 K−1 (8.34 W m−1 K−1) for Nb2GeTe4 in the x(y) direction. Besides, both monolayers express tremendous potential to further reduced lattice thermal conductivity by nano-structuring without requiring a diminished sample size that is technically challenging to synthesize.

Graphical abstract: The impact of electron–phonon coupling on the figure of merit of Nb2SiTe4 and Nb2GeTe4 ternary monolayers

Supplementary files

Article information

Article type
Paper
Submitted
03 May 2021
Accepted
24 Jun 2021
First published
24 Jun 2021

Phys. Chem. Chem. Phys., 2021,23, 15613-15619

The impact of electron–phonon coupling on the figure of merit of Nb2SiTe4 and Nb2GeTe4 ternary monolayers

M. Sajjad and N. Singh, Phys. Chem. Chem. Phys., 2021, 23, 15613 DOI: 10.1039/D1CP01967H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements