论文标题
通过弹道限制在语音金属中实现最小的热电导率
Achieving Minimal Heat Conductivity by Ballistic Confinement in Phononic Metalattices
论文作者
论文摘要
控制半导体的导热率是优化热电和声音设备的性能的实际兴趣。半导体中纳米大小的夹杂物的插入是实现这种对照的有效手段。已经提出，使用这种方法可以将硅的热导率降低至1 W/m/k，并且对于一定的最佳夹杂物尺寸，将达到热电导率的最小值。然而，该设计规则的实际验证受到限制。在这项工作中，我们通过研究硅金属的热性能来解决这个问题，该特性由从7到30 nm的半径夹杂物定期分布，嵌入硅中。实验测量结果证实，对于二氧化硅夹杂物，硅金属提克的热导率低至1 W/m/k，并且对于带空孔的硅金属矿石，该值可以进一步降低至0.16 W/m/k。弹道声子运输的详细模型表明，通过调整周期性不均匀性的半径和间距，这种导热率接近最低的最低电导率。这项研究是阐明缩放定律的重要一步，该定量定律决定了硅和其他半导体的纳米级弹道热传输。
Controlling the thermal conductivity of semiconductors is of practical interest in optimizing the performance of thermoelectric and phononic devices. The insertion of inclusions of nanometer size in a semiconductor is an effective means of achieving such control; it has been proposed that the thermal conductivity of silicon could be reduced to 1 W/m/K using this approach and that a minimum in the heat conductivity would be reached for some optimal size of the inclusions. Yet the practical verification of this design rule has been limited. In this work, we address this question by studying the thermal properties of silicon metalattices that consist of a periodic distribution of spherical inclusions with radii from 7 to 30 nm, embedded into silicon. Experimental measurements confirm that the thermal conductivity of silicon metalattices is as low as 1 W/m/K for silica inclusions, and that this value can be further reduced to 0.16 W/m/K for silicon metalattices with empty pores. A detailed model of ballistic phonon transport suggests that this thermal conductivity is close to the lowest achievable by tuning the radius and spacing of the periodic inhomogeneities. This study is a significant step in elucidating the scaling laws that dictate ballistic heat transport at the nanoscale in silicon and other semiconductors.
