Temperature-dependent transport properties of solids from first principles

根据第一原理得出的固体与温度相关的输运特性

• 批准号: 2470433
• 金额: --
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2470433
• 关键词: Temperature; dependent; transport; properties; solids

Many physical properties of functional materials are temperature-dependent, in part through the temperature dependence of the atomic vibrations in solids. A case in point are thermoelectric materials, which can be used to convert heat into electricity using solid-state semiconductor devices without any moving parts. Atomic vibrations and their temperature dependence affect all key properties of a thermoelectric material - electrical conductivity and Seebeck coefficient as well as the electronic and lattice contributions to the thermal conductivity. Despite this, the vast majority of first-principles electronic structure calculations are based on static-lattice, zero-kelvin calculations.The aim of this project is to model, from first principles, the effect of lattice vibrations at finite temperatures on the electronic structure and electronic transport properties of semiconductors, in particular thermoelectric materials. The project will explore and test the capabilities and limits of recent theory and software developments, which have been made available to the research community, e.g., in the abinit project. A central aim will beto make reliable predictions of the variation of the electronic band gap of semiconductors with temperature, a key factor that has so far been either ignored altogether or taken from experimental data where available. Candidate systems to be studied here include tin selenide, SnSe, and lead telluride, PbTe. These temperature-dependent simulations may be extended to also include effects of stresses and high pressure. Overall, this project will contribute towards improving the computational study and screening of new materials for energy applications.

功能材料的许多物理性质是温度相关的，部分原因是固体中原子振动的温度相关性。热电材料就是一个很好的例子，它可以利用固态半导体设备将热能转化为电能，而不需要任何移动部件。原子振动及其与温度的依赖关系影响热电材料的所有关键性质--电导率和塞贝克系数，以及电子和晶格对热导率的贡献。尽管如此，绝大多数第一性原理的电子结构计算都是基于静态晶格零开尔文计算。本项目的目的是从第一性原理出发，模拟有限温度下晶格振动对半导体，特别是热电材料的电子结构和电子输运性质的影响。该项目将探索和测试最近的理论和软件开发的能力和局限性，这些理论和软件开发已经向研究界提供，例如在abinit项目中。一个核心目标将是对半导体的电子带隙随温度的变化做出可靠的预测，这是一个关键因素，到目前为止要么被完全忽视，要么从可用的实验数据中获得。这里要研究的候选体系包括硒化锡，SnSe和碲化铅，PbTe。这些依赖于温度的模拟可以扩展到也包括应力和高压的影响。总体而言，该项目将有助于改进用于能源应用的新材料的计算研究和筛选。