二维新型过渡金属硫属化合物短周期平面超晶格的热输运性质调控研究

Micro-/nanoscale thermal transport has become the research hotspot in the field of engineering thermophysics. And lots of nanomaterials with excellent thermal transport properties are emerging. As an important nanostructure, superlattice exhibits unique physical properties being different from those of constituent materials, and is of great significance to the engineering applications. However, only few experimental and theoretical studies have been performed on the thermal transport properties of superlattice, and the limited researches are mainly focused on superlattice stacked by layers in the normal direction. Thus, the researches on short-period and two-dimensional (2D) atomic layer thick planar superlattice is largely lacking. The study of 2D superlattice design and thermal transport performance based on novel materials can not only enrich the fundamental research of 2D superlattice, but also pre-lay the basis for the applications of novel materials in the design of nanostructures and high-performance thermal management. This project will be conducted based on first-principles calculations, which constructs a class of 2D short-period planar superlattice from few novel 2D transition-metal dichalcogenides (TMDs). The influence of interface element composition and shape, together with temperature and strain on the thermal transport properties will be systematically studied. Moreover, based on the analysis of the phonon characteristics and the fundamental electronic structures, the microscopic mechanism and physical image of interface configuration will be established. This project would lay the theoretical foundation for the application of 2D TMDs short-period planar superlattice in the high-performance thermal management of functional devices.

微纳尺度热输运的研究已经成为当前工程热物理领域的研究热点，很多纳米材料表现出了非常优异的输运性质。超晶格作为一种重要的纳米结构，可表现出不同于组成单元材料的独特物理特性，具有工程上的应用意义。然而超晶格热输运性质的实验和数值模拟研究较少，且有限的研究主要集中在层层堆砌的超晶格，对于短周期及二维原子层厚平面超晶格的研究严重匮乏。基于新型材料的二维超晶格设计及热输运性能研究，不仅能丰富二维超晶格的基础研究，还可为新材料在纳米结构及特定热管理需求器件设计中的应用提前布局。本项目拟基于第一性原理方法，构建基于新型二维过渡金属硫属化合物的二维短周期平面超晶格，探究界面元素组成和形状以及温度和应变对其热输运性质的影响和调控规律，通过声子行为特征及底层电子信息的分析揭示并构建界面组态、温度和应变影响其热输运性质的微观机理和物理图像，为二维短周期平面超晶格在功能器件热管理中的应用奠定理论基础。

微纳尺度热输运研究已经成为当前工程热物理领域的研究热点，很多纳米材料和结构表现出了非常优异的热输运性质。异质结构超晶格作为一种重要的纳米结构，可表现出不同于所构成单元材料的独特物理特性，具有工程上的重要应用价值。本项围绕二维过渡金属硫属化合物材料平面特殊结构热输运特性展开研究，基于第一性原理计算，研究了外场（电场、温度）对过渡金属硫属化合物异质结构热输运性能的调控规律、热导率异常温度依赖效应、原子排列以及合金化对热导率的影响规律、孤立电子对或成键对热导率的影响规律、关联泛函选取及模型对热导率计算的影响规律和自旋-晶格耦合对二维体系热输运性能的影响规律。研究结果为二维过渡金属硫属化合物异质结构/超晶格在光电子/电子器件热管理以及热电转换领域的广泛应用奠定了理论基础。