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首页> 外文期刊>Physical review >Thermal conductance enhanced via inelastic phonon transport by atomic vacancies at Cu/Si interfaces
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Thermal conductance enhanced via inelastic phonon transport by atomic vacancies at Cu/Si interfaces

机译：通过Cu / Si接口的原子空位通过无弹性声子传输增强了热传导

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摘要

Understanding and controlling heat transfer across interfaces has become an important issue for the performance of micro- and nanoscale electronics, as well as achieving a high figure of merit for thermoelectrics. Intrinsic and extrinsic defects can have a significant impact on thermal transport in bulk materials and across interfaces, but the mechanism is not well understood. In this work, nonequilibrium molecular dynamics simulations are used to determine the impact of interfacial atomic vacancies on thermal transport across a Cu/Si junction. In contrast to the reduction in thermal transport typically seen with bulk defects, we find that by introducing atomic vacancies at a concentration of 6.3% near the interface in either or both materials, the interfacial thermal conductance can be increased by up to 76%. By controlling the initial positions of the vacancies and keeping track of their movements and population, we find that interfacial thermal transport is dependent on temperature, vacancy concentration, and distribution, and a positive correlation between the conductance and point defect activities (extent of vacancy migration, rate of Frenkel defect creation and annihilation) is observed. Further calculations based on the phonon density of states and normal mode decomposition reveal that the increase in interfacial thermal conductance originates primarily from high-frequency phonons, supported by enhanced inelastic phonon transport which contributes to more than 60% of the increase. Our findings suggest a practical way to manipulate inelastic phonon conversion through the presence of defects, which provides an alternative perspective on improving thermal transport between materials with a large lattice mismatch.
机译：理解和控制跨接口的热传递已成为微型和纳米电子和纳米电子和纳米电子产品的重要问题，以及实现热电测量的高值。内在和外在缺陷可能对散装材料和跨界面的热传输产生显着影响，但该机制尚不清楚。在这项工作中，非醌分子动力学模拟用于确定界面原子缺点对Cu / Si结的热传输的影响。与通常看过散装缺陷的热传输的减少相反，我们发现通过在任何一种或两种材料的界面附近的浓度为6.3％的原子空位，界面导热率可以增加高达76％。通过控制空缺的初始位置并跟踪它们的运动和群体，发现界面热传输依赖于温度，空位浓度和分布，以及导电和点缺陷活动之间的正相关（空缺迁移程度观察，弗雷克尔缺陷创作和湮灭的速度）。基于状态的声子密度和正常模式分解的进一步计算揭示了界面热传导的增加主要来自高频声子，由增强的无弹性声子传输支持，这有助于超过60％的增加。我们的研究结果表明，通过存在缺陷来操纵无弹性声子转换的实用方法，这提供了改善具有大格子不匹配的材料之间的热传输的替代方面。

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  • 来源
    《Physical review》 |2020年第7期|075449.1-075449.14|共14页
  • 作者

    Zexi Lu; Anne M. Chaka; Peter V. Sushko;

  • 作者单位

    Pacific Northwest National Laboratory Richland Washington 99352 USA;

    Pacific Northwest National Laboratory Richland Washington 99352 USA;

    Pacific Northwest National Laboratory Richland Washington 99352 USA;

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  • 正文语种 eng
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