论文标题

缺陷如何限制BAS的超高热电导率?第一原则研究

How do defects limit the ultrahigh thermal conductivity of BAs? A first principles study

论文作者

Fava, Mauro, Protik, Nakib Haider, Li, Chunhua, Ravichandran, Navaneetha Krishnan, Carrete, Jesús, van Roekeghem, Ambroise, Madsen, Georg K. H., Mingo, Natalio, Broido, David

论文摘要

如果不考虑掺杂材料时产生的减少,则无法评估通过BAS高热电导率来实现的承诺。使用第一原理计算,我们确定由BAS中不同组杂质引起的热导率降低,这是浓度和电荷状态的函数。我们揭露了一个普遍的趋势,中性杂质比被带电的杂质更强烈。 $ \ text {c} _ {\ text {b}} $和$ \ text {ge} _ {\ text {as}} $杂质显示出最弱的声子散射,并保留bas $κ$值$ \ sim $ \ sim $ 1000 $ \ text {w} \ cdot \ text {k}^{ - 1} \ cdot \ text {m}^{ - 1} $甚至最高的高密度,使其成为理想的N型和P-type掺杂剂。此外,超越了与费米水平相关的掺杂补偿阈值,固定触发了可观察到的导热率的变化。这为BAS掺杂的设计注意事项提供了信息,这也提出了一种直接的方法来确定实验样品中补偿掺杂的发作。

The promise enabled by BAs high thermal conductivity in power electronics cannot be assessed without taking into account the reduction incurred when doping the material. Using first principles calculations, we determine the thermal conductivity reduction induced by different group IV impurities in BAs as a function of concentration and charge state. We unveil a general trend, where neutral impurities scatter phonons more strongly than the charged ones. $\text{C}_{\text{B}}$ and $\text{Ge}_{\text{As}}$ impurities show by far the weakest phonon scattering and retain BAs $κ$ values of over $\sim$ 1000 $\text{W}\cdot\text{K}^{-1}\cdot\text{m}^{-1}$ even up to high densities making them ideal n-type and p-type dopants. Furthermore, going beyond the doping compensation threshold associated to Fermi level pinning triggers observable changes in the thermal conductivity. This informs design considerations on the doping of BAs, and it also suggests a direct way to determine the onset of compensation doping in experimental samples.

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