Wang Yu, Hamann Danielle M, Cordova Dmitri Leo M, Chen Jihan, Wang Bo, Shen Lang, Cai Zhi, Shi Haotian, Karapetrova Evguenia, Aravind Indu, Shi Li, Johnson David C, Cronin Stephen B
Department of Chemistry, University of Oregon, Eugene, Oregon 97403-1253, United States.
Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States.
Nano Lett. 2020 Nov 11;20(11):8008-8014. doi: 10.1021/acs.nanolett.0c02882. Epub 2020 Oct 23.
We explore the effect of charge density wave (CDW) on the in-plane thermoelectric transport properties of (PbSe)(VSe) and (PbSe)(VSe) heterostructures. In (PbSe)(VSe) 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)(VSe) 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)(VSe) material show the emergence of additional peaks below the CDW transition temperature associated with VSe material. Temperature-dependent in-plane X-ray diffraction (XRD) spectra show a change in the in-plane thermal expansion of VSe in (PbSe)(VSe) 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.
我们探究了电荷密度波（CDW）对（PbSe）（VSe）和（PbSe）（VSe）异质结构面内热电输运性质的影响。在（PbSe）（VSe）中，我们观察到在CDW转变过程中，塞贝克系数突然增加86%，功率因数增加245%，电阻率略有下降。在（PbSe）（VSe）中未观察到这种行为，与其他材料中观察到的一般趋势相比，这相当不寻常。这种突然转变通过相关电子态导致偏离莫特关系。（PbSe）（VSe）材料的拉曼光谱显示，在与VSe材料相关的CDW转变温度以下出现了额外的峰。随温度变化的面内X射线衍射（XRD）光谱表明，由于晶格畸变，（PbSe）（VSe）中VSe的面内热膨胀发生了变化。CDW导致的功率因数增加和电阻率降低表明了一种在低温区域提高热电性能的潜在机制。
