First Principles Studies of Novel Approach for Achieving Ultrahigh Thermal Conductivity in Materials

CBET-1402949 Broido随着微电子器件的不断缩小，散热正在成为一个日益关键的技术挑战。 迫切需要高导热性材料来应对这一挑战。 碳基晶体、金刚石、石墨、石墨烯和碳纳米管长期以来一直被认为具有迄今为止任何材料中最高的热导率。 特别是金刚石，被广泛用于电子设备的被动冷却，但其合成制造受到生长速度慢、成本高和质量低的影响。 尽管有明确的标准来指导寻找新的高#954;材料，但多年来几乎没有取得进展。 使用精确的第一原理理论方法，我们最近发现了一种意想不到的材料，砷化硼应该具有与金刚石相当的极高的热导率。 这一令人惊讶的发现源于基本的材料特性，其中一些通常与高#954;材料的处方无关。 该项目的目标是详细研究砷化硼的热传输特性，并使用砷化硼的材料搜索范例来识别新的高#954;材料。 因此，该项目将有助于解决散热挑战，并通过帮助开发新的高#954;材料来造福社会。这将促进技术突破，可能会导致下一代被动冷却设备的电子产品，如散热器和散热器。这项研究工作将实施一个国家的最先进的，第一原理的热传输方法，以提供我们最近发现的异常高的砷化硼的基本理解，并提出了新的范例，以实现材料的高导热性。 这种方法的一个核心特征是它没有可调参数。此外，它已经证明了与广泛材料的测量热导率的良好一致性，验证了其预测能力。 将砷化硼中发现的新材料特性与高效的计算算法相结合，将用于广泛搜索一类新的新型高性能材料。 这将有助于发现尚未确定的高#954;材料。 更深入地了解缺陷的作用，并深入了解如何调整所需的材料性能，以提高#954;也将进行调查。 该项目提供了重要的新见解材料的导热性的性质，指导测量工作，并促进设计和热管理应用的高#954;材料。

CBET-1402949BroidoAs microelectronic devices continue to shrink, heat dissipation is becoming an increasingly critical technology challenge. High thermal conductivity materials are urgently needed to address this challenge. The carbon-based crystals, diamond, graphite, graphene and carbon nanotubes have long been known to have by far the highest thermal conductivities, κ, of any material. Diamond, in particular, is widely used for passive cooling of electronics, but its synthetic fabrication suffers from slow growth rates, high cost, and low quality. In spite of well-defined criteria to guide the search for new high κ materials, little progress has been made over the years. Using an accurate, first principles, theoretical approach, we have recently found that an unexpected material, boron arsenide should have exceptionally high thermal conductivity, comparable to that of diamond. This surprising finding stems from fundamental material properties, some of which are not typically connected to prescriptions for high κ in materials. The objectives of this project will be to study in detail the thermal transport properties of boron arsenide, and to identify new high κ materials using the materials search paradigm identified for boron arsenide. This project will therefore help address the heat dissipation challenge and benefit society by aiding in the development of new high κ materials. This will facilitate technological breakthroughs that may lead to the next generation of passive cooling devices for electronics, such as heat spreaders and heat sinks.This research effort will implement a state-of-the-art, first principles thermal transport approach to provide fundamental understanding of our recent finding of exceptionally high κ in boron arsenide and the proposed new paradigm for achieving high thermal conductivity in materials. A central feature of this approach is that it has no adjustable parameters. Furthermore, it has already demonstrated excellent agreement with measured thermal conductivities for a wide range of materials, validating its predictive capability. Efficient computational algorithms incorporating the novel material properties found in boron arsenide will be used to implement a broad search for a new class of novel high κ materials. This will facilitate the discovery of as yet unidentified high κ materials. Deeper understanding of the role of defects and insight into how to tune the desirable material properties to enhance κ will also be investigated. This project with provide important new insights into the nature of thermal conductivity in materials, give guidance to measurement efforts, and facilitate the design and of high κ materials for thermal management applications.