期刊
MATERIALS TODAY PHYSICS
卷 22, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.mtphys.2021.100599
关键词
Anisotropy; Thermal conductivity; Phonon dispersion; Inelastic X-ray scattering; PdSe2
资金
- National Key R&D Program of China [2021YFA1400300]
- National Natural Science Foundation of China [12172047]
- Beijing Natural Science Foundation [Z190011]
- Doctoral Foundation of Henan Polytechnic University (Natural Science)
- DOE Office of Science [DE-AC02-06CH11357]
An exceptional case of thermal conductivity anisotropy in layered pentagonal PdSe2 is reported. The thermal conductivity along the b-axis is surprisingly much greater than along the a-axis. The high anisotropy is attributed to the low-energy phonons along the a-axis and the different buckling structures between the a-axis and the b-axis.
In two-dimensional materials, different atomic stacking induces anisotropic atomic interactions and phonon dispersions, leading to the anisotropy of in-plane thermal transport. Here, we report an exceptional case in layered pentagonal PdSe2, where the bonds, force constants, and lattice constants are nearly-equal along the in-plane crystallographic axis directions, while the thermal conductivity is surprisingly much greater along b-axis than along a-axis with a ratio up to 1.8. Such strong anisotropy is not only unexpected in in-plane uniform structured materials, but also comparable to the record high in-plane anisotropic thermal conductivity in the nonuniform structured material reported to date (the ratio is similar to 2.0 in TiS3). By combining the inelastic X-ray scattering measurement and the first-principles calculations, we attribute such high anisotropy to the low-energy phonons along a-axis, particularly their lower group velocities and avoided-crossing behavior. The different buckling structures between a- (zigzag-type) and b-axis (flat-type) are mainly responsible for such unique phonon dynamics properties of PdSe2. This finding helps to discover materials with high anisotropic in-plane thermal conductivity in uniform structures and reveals new physics of anisotropy of in-plane thermal conduction. Due to the unique features in structure and thermal transport properties, PdSe2 may serve as a new platform for designing novel devices to route heat flow precisely at the nanoscale. (C) 2021 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据