Vibrational properties and phonon transport of nanobridges (A08*)

纳米桥的振动特性和声子传输 (A08*)

• 批准号: 285679965
• 金额: --
• 依托单位: Lehrstuhl für Theoretische Physik I
• 依托单位国家: 德国
• 项目类别: Collaborative Research Centres
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/285679965?language=en
• 关键词: Vibrational; properties; phonon; transport; nanobridges

We will study how vibrational properties of nanobridges can be tuned through temperature and mechanical stress. Developing an ab-initio description based on density functional theory, we will include anharmonic effects to consider their influence on the heat current by phonons and its fluctuations. Within this methodology that allows to determine phonon lifetimes based on phonon-phonon scattering, we will focus on molecular and atomic scale junctions. We will explore the dependence of phonon transport on molecular shape, conjugation, anchoring groups, substituents and electrode materials as well as ways to achieve a suppression of thermal conductance through destructive phonon inter-ference and increased anharmonicities. Finally, using molecular dynamics and force fields, calibrated with the ab-initio approach, we will explore a new type of thermal diode that exploits different thermal expansion coefficients to achieve a high rectification ratio.

我们将研究如何通过温度和机械应力来调节纳米桥的振动特性。在密度泛函理论的基础上建立一个从头开始的描述，我们将包括非谐波效应，以考虑它们对声子热流及其波动的影响。在这种方法中，允许根据声子-声子散射确定声子寿命，我们将重点关注分子和原子尺度的结。我们将探索声子输运对分子形状、共轭、锚定基团、取代基和电极材料的依赖，以及通过破坏性声子干涉和增加非调和性来实现热导抑制的方法。最后，利用分子动力学和力场，用从头算方法校准，我们将探索一种新型的热二极管，利用不同的热膨胀系数来实现高整流比。