School of Engineering and Applied Science, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA.
Science. 2018 Aug 10;361(6402):575-578. doi: 10.1126/science.aat5522. Epub 2018 Jul 5.
Improving the thermal management of small-scale devices requires developing materials with high thermal conductivities. The semiconductor boron arsenide (BAs) is an attractive target because of ab initio calculation indicating that single crystals have an ultrahigh thermal conductivity. We synthesized BAs single crystals without detectable defects and measured a room-temperature thermal conductivity of 1300 watts per meter-kelvin. Our spectroscopy study, in conjunction with atomistic theory, reveals that the distinctive band structure of BAs allows for very long phonon mean free paths and strong high-order anharmonicity through the four-phonon process. The single-crystal BAs has better thermal conductivity than other metals and semiconductors. Our study establishes BAs as a benchmark material for thermal management applications and exemplifies the power of combining experiments and ab initio theory in new materials discovery.
提高小型设备的热管理水平需要开发具有高热导率的材料。半导体砷化硼 (BAs) 是一个很有吸引力的目标，因为从头算计算表明，其单晶具有超高的热导率。我们合成了没有明显缺陷的 BAs 单晶，并测量了其在室温下的热导率为 1300 瓦/米·开尔文。我们的光谱研究与原子理论相结合，揭示了 BAs 的独特能带结构使得声子平均自由程非常长，并且通过四声子过程具有很强的高阶非谐性。单晶 BAs 的热导率优于其他金属和半导体。我们的研究确立了 BAs 作为热管理应用的基准材料，并展示了结合实验和从头算理论在新材料发现中的力量。
