Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA.
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science. 2018 Aug 10;361(6402):582-585. doi: 10.1126/science.aat7932. Epub 2018 Jul 5.
Conventional theory predicts that ultrahigh lattice thermal conductivity can only occur in crystals composed of strongly bonded light elements, and that it is limited by anharmonic three-phonon processes. We report experimental evidence that departs from these long-held criteria. We measured a local room-temperature thermal conductivity exceeding 1000 watts per meter-kelvin and an average bulk value reaching 900 watts per meter-kelvin in bulk boron arsenide (BAs) crystals, where boron and arsenic are light and heavy elements, respectively. The high values are consistent with a proposal for phonon-band engineering and can only be explained by higher-order phonon processes. These findings yield insight into the physics of heat conduction in solids and show BAs to be the only known semiconductor with ultrahigh thermal conductivity.
传统理论预测超高晶格热导率只能出现在由强键合轻元素组成的晶体中，并受非谐三声子过程限制。我们报告了与这些长期以来的标准相背离的实验证据。我们在块状砷化硼（BAs）晶体中测量到局部室温热导率超过 1000 瓦/米-开尔文，平均体热导率达到 900 瓦/米-开尔文，其中硼和砷分别是轻元素和重元素。这些高值与声子能带工程的建议一致，只能用更高阶的声子过程来解释。这些发现深入了解了固体热传导的物理性质，并表明 BAs 是唯一已知的具有超高热导率的半导体。
