Enhanced Low-Temperature Thermoelectric Performance in (PbSe)1+δ(VSe2)1 Heterostructures due to Highly Correlated Electrons in Charge Density Waves

Yu Wang; Danielle M Hamann; Dmitri Leo M Cordova; Jihan Chen; Bo Wang; Lang Shen; Zhi Cai; Haotian Shi; Evguenia Karapetrova; Indu Aravind; Li Shi; David C Johnson; Stephen B Cronin

doi:10.1021/acs.nanolett.0c02882

Enhanced Low-Temperature Thermoelectric Performance in (PbSe)_1+δ(VSe₂)₁ Heterostructures due to Highly Correlated Electrons in Charge Density Waves

Nano Lett. 2020 Nov 11;20(11):8008-8014. doi: 10.1021/acs.nanolett.0c02882. Epub 2020 Oct 23.

Authors

Yu Wang, Danielle M Hamann¹, Dmitri Leo M Cordova¹, Jihan Chen, Bo Wang, Lang Shen, Zhi Cai, Haotian Shi, Evguenia Karapetrova², Indu Aravind, Li Shi³, David C Johnson¹, Stephen B Cronin

Affiliations

¹ Department of Chemistry, University of Oregon, Eugene, Oregon 97403-1253, United States.
² Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States.
³ Department of Mechanical Engineering and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, United States.

PMID: 33095023
DOI: 10.1021/acs.nanolett.0c02882

Abstract

We explore the effect of charge density wave (CDW) on the in-plane thermoelectric transport properties of (PbSe)_1+δ(VSe₂)₁ and (PbSe)_1+δ(VSe₂)₂ heterostructures. In (PbSe)_1+δ(VSe₂)₁ we observe an abrupt 86% increase in the Seebeck coefficient, 245% increase in the power factor, and a slight decrease in resistivity over the CDW transition. This behavior is not observed in (PbSe)_1+δ(VSe₂)₂ and is rather unusual compared to the general trend observed in other materials. The abrupt transition causes a deviation from the Mott relationship through correlated electron states. Raman spectra of the (PbSe)_1+δ(VSe₂)₁ material show the emergence of additional peaks below the CDW transition temperature associated with VSe₂ material. Temperature-dependent in-plane X-ray diffraction (XRD) spectra show a change in the in-plane thermal expansion of VSe₂ in (PbSe)_1+δ(VSe₂)₁ due to lattice distortion. The increase in the power factor and decrease in the resistivity due to CDW suggest a potential mechanism for enhancing the thermoelectric performance at the low temperature region.

Keywords: Charge density wave; energy conversion; many body; thermoelectricity; thermoelectrics; transition-metal dichalcogenide.