Transport Properties of Few-Layer NbSe2: from Electronic Structure to Thermoelectric Properties

Published

July 20, 2022

Author(s)

Tianhui Zhu, Peter Litwin, Md Golam Rosul, Devin Jessup, Md Sabbir Akhanda, Farjana Tonni, Sergiy Krylyuk, Albert Davydov, Petra Reinke, Stephen McDonnell, Mona Zebarjadi

Abstract

4-layer NbSe2 is grown on SiO2 by molecular beam epitaxy. The in-situ X-ray photoelectron spectroscopy (XPS) measurements suggest a Nb-rich stoichiometry (Nb1+xSe2) likely due to intercalation of Nb atoms in between the NbSe2 layers. The metallic nature of the samples is confirmed using scanning tunnelling microscopy and local density of state measurements as well as band structure calculations. This metallic nature is consistent with the small measured Seebeck coefficient and large electrical conductivity values. A change of sign in the Seebeck coefficient is observed in the bulk single crystal sample at 50 K, and in the polycrystalline few-layer sample at 120 K. The room temperature Seebeck coefficient is negative, but when oxidized, that of the few-layer sample changed to positive. The in-plane thermal conductivity of the few-layer samples is measured using the heat diffusion imaging method at low temperatures and is (32 ± 10) W/m∙K at 200 K.

Citation

Materials Today Physics

Volume

27

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.mtphys.2022.100789

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Keywords

two-dimensional materials, molecular beam epitaxy, transition metal dichalcogenides, niobium selenide, thermoelectric, density functional theory, scanning tunneling microscopy

Citation

Zhu, T. , Litwin, P. , Rosul, M. , Jessup, D. , Akhanda, M. , Tonni, F. , Krylyuk, S. , Davydov, A. , Reinke, P. , McDonnell, S. and Zebarjadi, M. (2022), Transport Properties of Few-Layer NbSe2: from Electronic Structure to Thermoelectric Properties, Materials Today Physics, [online], https://doi.org/10.1016/j.mtphys.2022.100789, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934088 (Accessed April 26, 2024)