凝聚态物理
热导率
电场
材料科学
铁电性
钛酸钡
相变
电介质
玻尔兹曼方程
电导率
热传导
声子
无定形固体
热力学
物理
化学
量子力学
光电子学
结晶学
复合材料
作者
Chenhan Liu,Vivek Mishra,Yunfei Chen,Chris Dames
标识
DOI:10.1002/adts.201800098
摘要
Abstract The thermal conductivity of crystalline materials is typically one or two orders of magnitude higher than that of their amorphous structures. The phase transition in barium titanate is generally considered to exhibit order–disorder character, suggesting the potential for thermal conductivity switching if this order–disorder transition can be controlled. To investigate this possibility computationally, following the method of Fu and Bellaiche, here electric fields are applied to align the polarizations and transform disordered paraelectric structures to ordered ferroelectric structures. Solving the Boltzmann transport equation, the theoretical limit of a perfectly disordered structure is found to have thermal conductivity of a factor of 3.9 lower than the perfectly ordered structure. The thermal conductivity of the ordered structure can be further enhanced by up to another 2.4 times under electric fields due to the reduction in phonon scattering rates, implying a theoretical maximum thermal conductivity switching ratio of 9.4. This study yields two guidelines in searching for high thermal conductivity switch ratio in ferroelectric materials: the structure should be single domain under electric field and the phase transition should be fully order–disorder rather than displacive.
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