Anomalous energy transfer in crystalline materials from the viewpoints of discrete mechanics and continuum theory

从离散力学和连续介质理论的角度研究晶体材料中的反常能量传递

• 批准号: 405631704
• 负责人: Professor Dr. Wolfgang H. Müller
• 金额: --
• 依托单位: Fachgebiet Kontinuumsmechanik und Materialtheorie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/405631704?language=en
• 关键词: Anomalous; energy; transfer; crystalline; materials

This project focuses on theoretical and experimental studies of anomalous energy transfer by heat conduction in crystalline lattices. At the nanoscale materials exhibit special thermomechanical properties mostly related to the discreteness of the atomic structure of the medium. An understanding of the energy transfer by heat conduction at that level is essential to obtain a link between the microscopic and the macroscopic descriptions of solids. Latest developments in technology made it possible to investigate properties of low dimensional objects, such as nanotubes, graphene, or fullerenes. During the last decades it was shown that in low dimensional structures, where the phonon mean free path is small compared to the structural size, the nature of heat propagation is ballistic rather than diffusive. Electrical and mechanical properties of low dimensional crystalline structures became of interest during the last decades due to applications in microelectronic devices. Problems of energy transport by heat conduction are of great importance due to problems of cooling and designing innovative thermal devices. Miniaturization of electronic devices and circuits has led to the emergence of self-heating as a critical bottleneck to the performance and reliability of newly developed microelectronic circuits and systems. In order to address heat transfer physics at the single device level, more advanced models of energy transport by heat conduction should be considered. This motivates recent interest in investigating thermal properties of the structures, such as graphene and carbon nanotubes, where such anomalies are most prominent. The aim of this proposal is to investigate anomalous energy transport by heat conduction in low dimensional structures using analytical approaches and simulations, which will help to design and interpret experiments to be performed in order to validate theoretical model predictions.The following will be investigated:- Formulation of discrete and continuous models of anomalous energy transfer in 1D and quasi-1D crystalline materials.- Description of anomalous energy transfer in 2D materials of simple structure.- Development of 2D lattice and continuum models. - Simulation of the energy transfer by heat conduction in such systems using discrete and continuum approaches.- Analogous experiments for the transient case.- Performing experiments determining thermal parameters of nano-structures (graphene) in the non-steady regime using Raman spectroscopy and AFM thermosensors.- Comparison and interpretation of experimental data with results of simulation and analytical studies.Our main objectives:- Create a theory of energy propagation by heat conduction in crystals based on first principles.- Investigate its consistency with extended thermodynamics and phenomenological theories. - Test the models in custom designed experiments

该项目的重点是晶格中热传导异常能量转移的理论和实验研究。在纳米级，材料具有特殊的热机械特性，主要与培养基原子结构的离散性有关。在该水平上对热传导的能量传递的理解对于获得固体的显微镜和宏观描述之间的联系至关重要。技术方面的最新发展使得可以研究低维对物体的属性，例如纳米管，石墨烯或富勒烯。在过去的几十年中，在低维结构中，声子平均自由路径与结构大小相比很小，热传播的性质是弹道而不是扩散的。在过去几十年中，由于微电器设备的应用，低维晶体结构的电气和机械性能引起了人们的关注。由于冷却和设计创新的热设备的问题，通过热传导的能量传输问题非常重要。电子设备和电路的微型化导致了自加热的出现，这是对新开发的微电子电路和系统的性能和可靠性的关键瓶颈。为了解决单个设备级别的传热物理，应考虑通过热传导的更先进的能量传输模型。这激发了最近研究结构的热性能的兴趣，例如石墨烯和碳纳米管，这些异常是最突出的。该提案的目的是使用分析方法和模拟研究低维结构中的热能传输，这将有助于设计和解释要进行的实验，以验证理论模型预测。将研究以下内容。 2D晶格和连续模型。 - 使用离散和连续方法在此类系统中通过热传导对能量转移进行模拟。-对瞬态案例进行类似实验。-执行实验确定非稳态制度的纳米结构的热参数（石墨烯）在非稳态方向上使用拉曼光谱和AFM热传感器进行了模拟和解释的方法。通过基于第一原理的晶体传导。-研究其与扩展的热力学和现象学理论的一致性。 - 测试自定义设计实验中的模型