低维系统界面热阻和温度跃变的微观机制研究

With the rapid development of nanotechnology, interfacial thermal resistance becomes the main technical bottleneck to superintegrate electronic components at micro-to-nano scale and received more and more attentions from communities of engineering physics, condensed matter physics and statistical physics. However, its microscopic mechanism has not been fully understood up to now. This project aims to study microscopic mechanism of the interfacial temperature jump of low dimensional systems by using theoretical analysis as well as nonequilibrium numerical calculations, and understand the microscopic origin of negative temperature jump. Meanwhile, this project also aim to develop and improve the analytical approaches to interfacial thermal conduction. The main contents of this project are: (1) conditions for the occurrence of negative temperature jump and its relation to interfacial structure; (2)developing self-consistent phonon theory by combining generalized Langevin equations and Green's function method; (3) the effects of interfacial property on interfacial thermal resistance and studies of temperature and local equilibrium inside interface. We believe this project will reveal the microscopic mechanism of interfacial thermal resistance, further deepen our understandings on some basic concepts of statistical physics, and finally provide new inspirations for designing novel thermal devices at micro-to-nano scale.

随着纳米技术的迅猛发展，界面热阻成了在微纳米尺寸上高密度集成电子元器件的主要技术瓶颈，其研究受到了来自工程物理、凝聚态物理及统计物理等领域的广泛关注。但是界面热阻的微观机制至今尚未得到全面的理解。本项目拟采用理论分析和非平衡态数值计算相结合的方法，深入研究低维系统界面处温度跃变的微观机制，揭示负温度跃变的微观起源，同时发展低维非线性系统界面热传导的理论方法。主要研究内容包括：（1）负温度跃变出现的条件及其和界面结构的关系；（2）结合广义郎之万方程和格林函数方法，进一步发展自适应声子理论；（3）界面性质对界面热阻的影响以及界面温度和局域平衡态的研究。本项目将揭示低维系统界面热阻的微观机制，加深人们对统计物理若干基本概念的理解，并为在微纳米尺寸上研发制备新型热器件提供新的思路。

本项目拟重点解决的主要科学问题是低维系统界面处温度跳跃的微观机制。我们研究发现反常温度跃变来源于界面局域化的声子的存在，较圆满解决了本项目的核心科学问题。在热传导理论研究方面，我们发展了量子自适应声子理论，并提出了非马尔科夫热输运理论。另外，我们也发现了修正对数势导致维里定理和广义能均分定律不成立，并提出了非线性晶格温度的解析计算方法。在界面热传导应用方面，我们发现分子间电子迁移可导致热电整流效应。这些结果使得我们进一步认识了界面热传导的微观机理，并对统计物理中的一些基本概念、定理有了新的理解。项目研究相关结果已整理成7篇学术论文在物理学主流刊物上发表。