人工晶体学报, 2020, 49 (12): 2292, 网络出版: 2021-01-26
二维CdO的低晶格热导率研究
Investigation of Low Lattice Thermal Conductivity in Two-Dimensional CdO
摘要
寻求具有较小晶格热导率klat的高热电性能的二维材料具有重要意义。基于从头计算和声子玻耳兹曼输运理论,该研究首先对二维CdO结构进行优化,并通过计算声子谱验证了单层CdO的动力学稳定性。在此基础上详细研究了单层CdO的声子输运性质。计算表明在室温下单层CdO的晶格热导率klat约为5.7 W/(m·K),低于单层石墨烯、磷烯、黑磷和MoS2等二维材料的晶格热导率。其中,Z方向声学模式(Z-direction acoustic, ZA),横声学支(transverse acoustic,TA),纵声学支(longitudinal acoustic, LA),Z方向光学模式(Z-direction optical, ZO),横光学支(transverse optical, TO),纵光学支(longitudinal optical, LO)对klat的百分比贡献分别为73.7%、13.9%、3.7%、2.8%、4.7%和1.2%。研究发现,ZA、TA、LA声学支和光学支之间的强散射是导致单层CdO低热导率的原因。本文计算结果可用于指导基于CdO的低维热电器件的设计。
Abstract
Seeking two-dimensional materials with low lattice thermal conductivity (klat)is of great significance to enhance high thermoelectric performance. Based on ab-initio calculations and phonon Boltzmann transport theory, the structure of two-dimensional CdO is optimized and the dynamic stability of monolayer CdO is verified by calculating phonon spectra. The phonon transport properties of monolayer CdO were studied in detail. The results show that the lattice thermal conductivity of monolayer CdO is around 5.7 W/(m·K) at room temperature, which is much lower than that of monolayer graphene, buckled monolayer phosphorene, monolayer black phosphorene, and MoS2. The percentage contribution of Z-direction acoustic (ZA), transverse acoustic(TA), longitudinal acoustic(LA), Z-direction optical (ZO), transverse optical(TO) and longitudinal optical (LO) branches to klat is 73.7%, 13.9%, 3.7%, 2.8%, 4.7% and 1.2%, respectively. The strong scattering among optical-acoustic phonons is found to be responsible for the low thermal conductivity of monolayer CdO. The calculated results could guide the design of CdO-based low-dimensional thermoelectric devices.
刘雪飞, 罗子江, 吕兵. 二维CdO的低晶格热导率研究[J]. 人工晶体学报, 2020, 49(12): 2292. LIU Xuefei, LUO Zijiang, LYU Bing. Investigation of Low Lattice Thermal Conductivity in Two-Dimensional CdO[J]. Journal of Synthetic Crystals, 2020, 49(12): 2292.