分形 Lévy 热输运在纳米颗粒嵌入半导体合金中的应用。

Fractal Lévy Heat Transport in Nanoparticle Embedded Semiconductor Alloys.

机构信息

†Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States.

‡Materials Department, University of California, Santa Barbara, California 93106, United States.

出版信息

Nano Lett. 2015 Jul 8;15(7):4269-73. doi: 10.1021/nl5044665. Epub 2015 Feb 9.

DOI:10.1021/nl5044665

PMID:25654652

Abstract

Materials with embedded nanoparticles are of considerable interest for thermoelectric applications. Here, we experimentally characterize the effect of nanoparticles on the recently discovered Lévy phonon transport in semiconductor alloys. The fractal space dimension α ≈ 1.55 of quasiballistic (superdiffusive) heat conduction in (ErAs)x:InGaAlAs is virtually independent of the Er content 0.001 < x < 0.1 but instead controlled by alloy scattering of the host matrix. The increased nanoparticle concentration does reduce the diffusive recovery length by an order of magnitude. The bulk conductivity drops by 3-fold, in close agreement with a Callaway model. Our results may provide helpful hints toward engineering superdiffusive heat transport similar to what has been achieved with light in Lévy glasses.

摘要

具有嵌入式纳米粒子的材料在热电应用中具有相当大的兴趣。在这里，我们通过实验来研究纳米粒子对最近发现的半导体合金中 Lévy 声子输运的影响。在（ErAs）x:InGaAlAs 中，拟弹道（超扩散）热传导的分形空间维度 α ≈ 1.55几乎与 Er 含量 0.001 < x < 0.1 无关，而是由主体矩阵的合金散射控制。增加纳米粒子浓度会将扩散恢复长度降低一个数量级。体电导率下降了 3 倍，与 Callaway 模型非常吻合。我们的结果可能为工程超扩散热传输提供有用的提示，类似于在 Lévy 玻璃中实现的光传输。