Significant phase-space-driven thermal transport suppression in BC8 silicon
Significant phase-space-driven thermal transport suppression in BC8 silicon
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DOI：
10.1016/j.mtphys.2021.100566
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发表时间：
2021-10
影响因子：
11.5
通讯作者：
Junyan Liu;T. Strobel;H. Zhang;D. Abernathy;Chen W. Li;Jia-wang Hong
中科院分区：
文献类型：
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作者：
Junyan Liu;T. Strobel;H. Zhang;D. Abernathy;Chen W. Li;Jia-wang Hong
BC 8硅同素异形体具有比金刚石-立方硅低1-2个数量级的晶格热导率。在目前的工作中，声子态密度，声子色散和晶格热导率的非弹性中子散射测量和第一性原理计算进行了研究。研究发现，在BC 8-Si中，平坦声子带在晶格热导率的降低中起着关键作用。这种在低能量范围内的频带增强了声学声子和低能量光学声子之间的声子散射，而在中间能量范围内的频带充当高能量光学声子和低能量光学声子之间的散射桥梁。它们显著地扩大了这种新型硅同素异形体中的声子-声子散射相空间并降低了晶格热导率。这项工作为BC 8-Si中晶格热导率的显着降低提供了见解，从而扩展了对新型硅同素异形体及其电子器件开发的理解。
The BC8 silicon allotrope has a lattice thermal conductivity 1–2 orders of magnitude lower than that of diamond-cubic silicon. In the current work, the phonon density of states, phonon dispersion, and lattice thermal conductivity are investigated by inelastic neutron scattering measurements and first-principles calculations. Flat phonon bands are found to play a critical role in the reduction of lattice thermal conductivity in BC8–Si. Such bands in the low-energy range enhance the phonon scattering between acoustic and low-energy optical phonons, while bands in the intermediate-energy range act as a scattering bridge between the high- and low-energy optical phonons. They significantly enlarge the phonon-phonon scattering phase space and reduces the lattice thermal conductivity in this novel silicon allotrope. This work provides insights into the significant reduction of the lattice thermal conductivity in BC8–Si, thus expanding the understanding of novel silicon allotropes and their development for electronic devices.