Roles of Point Defects in Thermal Transport in Perovskite Barium Stannate
Roles of Point Defects in Thermal Transport in Perovskite Barium Stannate
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DOI：
10.1021/acs.jpcc.8b00653
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发表时间：
2018-05-31
影响因子：
3.7
通讯作者：
Hou, Yu
中科院分区：
文献类型：
--
作者：
Chen, Liang;Zhang, Yingying;Hou, Yu
钙钛矿锡酸钡（BaSnO3）是光电子器件中透明导电氧化物和高迁移率氧化物电子器件中的通道材料，是一种很有前途的候选材料。在这项工作中，我们计算了晶格导热系数，并研究了点缺陷对BaSnO3中热输运的影响，这是基于第一性原理计算的原子间力常数声子玻尔兹曼输运方程。在原始的BaSnO3中，我们发现在300 K时，声子对热输运的贡献占54%，其余部分归因于具有较高群速度的低频（27.5-50 THz）光学模式。我们发现氧空位和杂质会导致BaSnO3的热导率明显降低，但相应的机制在不同声子模式下的散射速率不同。300 K时氧空位导致的导热系数降低主要是由于声子和低频光声子散射增加所致。镧和钾杂质主要增加声子的散射，而锑杂质通过增加优势声子的散射率来降低热导率，包括声模式和低频光模式。这些结果和发现有助于我们更好地理解钙钛矿氧化物的热输运机制，重点是氧空位和杂质对BaSnO3热性能的影响。
Perovskite barium stannate (BaSnO3) is a promising candidate that can be used as transparent conducting oxide in optoelectronic devices and as the channel material in high-mobility oxide electronics. In this work, we calculate the lattice thermal conductivity and investigate the impact of point defects on thermal transport in BaSnO3 based on the phonon Boltzmann transport equations with interatomic force constants from first-principles calculations. In pristine BaSnO3, we find the contribution of acoustic phonons to thermal transport accounts for 54% at 300 K and the rest is attributed to the lower-frequency (27.5-50 THz) optical modes with relatively high group velocity. We show oxygen vacancies and impurities can cause noticeable reduction in thermal conductivity of BaSnO3, but the corresponding mechanisms differ in terms of scattering rates on different phonon modes. The thermal conductivity reduction due to oxygen vacancies at 300 K is mainly caused by the increased scattering of the acoustic phonons and the low-frequency optical phonons. Lanthanum and potassium impurities mainly increase the scattering of acoustic phonons, but antimony impurity lowers the thermal conductivity by increasing the scattering rate of dominant phonons, including both the acoustic modes and the low frequency optical modes. The results and findings facilitate us to better understand the thermal transport mechanisms of perovskite oxides with an emphasis on the impact of oxygen vacancies and impurities on the thermal properties of BaSnO3.