拓扑半金属材料生长及其缺陷影响的第一性原理研究

Topological semimetal, as a new class of topological electronic states with rich and fascinating physics, has important application prospects in the fields of spintronics and topological quantum computing. However, there are still many important challenges to be conquered in the field, such as material preparation and the observation of topological electronic states. Based on first-principles calculations and tight-binding approximations, aiming at the material growth and the defect physics of topological semimetal, this project focuses on the following tasks: 1. From the perspective of material growth, we will study the preparation process of the topological semimetal materials. Combined with the reaction thermodynamics and molecular dynamics analysis, we will provide the optimal growth conditions for the preparation of samples. 2. To clarify the difficulty and the role of microstructure such as defect states and impurity atoms in topological semimetals, and provide prediction and guidance for material synthesis and property modulation. 3. Combined with Monte Carlo simulation, we will investigate the effects of defect states and impurity atoms on the topological, electronic and magnetic properties of topological semimetals, based on the comparison of microcosmic interactions with macroscopic properties. Finally, we try to reveal the regulation of microstructure on the material properties in topological semimetals. Through these studies, we will offer a guidance for the experimental preparation of real materials, and for the observation of topological electronic states in topological semimetals. In addition, we aim to comprehensive understand of the materials growth mechanism of topological semimetals as well as the microstructure-induced changes in physical properties, so as to lay a foundation for the industrial applications of topological semimetals.

拓扑半金属是一类全新的拓扑电子态，具有丰富又迷人的物理，在自旋电子学和拓扑量子计算等领域具有重要的应用前景。然而，该领域仍面临着材料制备、拓扑电子态观测等重要挑战。本项目基于第一性原理计算和紧束缚近似方法，瞄准拓扑半金属的材料生长及其缺陷影响，集中开展以下几项工作：1.从材料生长的角度，研究拓扑半金属系列材料的制备过程，结合反应热力学和分子动力学分析给出样品制备最优化的生长条件。2.阐明缺陷态、杂质原子等微结构在拓扑半金属中的存在状态及其产生的影响，为材料合成、性能调控提供预测和指导。3.结合Monte Carlo模拟，在微观相互作用与宏观特性比较的基础上，研究缺陷态及杂质原子对拓扑半金属的拓扑特性、电学性质、磁性的影响，揭示微结构对材料物性的调控规律。通过项目研究指导拓扑半金属真实材料的实验获取和观测，全面理解材料的生长机理以及微结构诱导的物性变化规律，为拓扑半金属的工业应用奠定基础。

拓扑半金属作为继拓扑绝缘体后，近年来涌现的又一类重要的、全新拓扑电子态，具有丰富又迷人的物理，而且在自旋电子学和拓扑量子计算等领域具有重要的应用前景。然而，该领域面临着材料生长制备、拓扑物性观测和外场调控等重要挑战。.本项目主要通过第一性原理计算结合紧束缚近似方法等展开研究。取得的主要成果包括：（1）在稀土氮磷族拓扑半金属HoSb、CeSb、LuBi和YBi等多个材料的拓扑物性、磁电阻效应和生长制备等方面取得重要进展；获得了拓扑半金属Y2Ir2O7中缺陷对电子结构等的重要影响。（2）Bi2Se3系列拓扑材料及其磁性掺杂体系中的物性调控取得重要进展。（3）MnBi2Te4等本征磁性拓扑绝缘体拓扑物性和调控方面工作取得重要进展。（4）二维拓扑材料物性研究方面取得重要进展。（5）在自旋零带隙半导体材料PbPdO2的拓扑物性及性能调控上取得重要成果。.项目完成了对多个拓扑半金属、新型拓扑量子体系材料生长机理、缺陷作用、电子结构、拓扑性质及外场调控等的研究，为实验研究提供了重要依据，并为拓扑材料的工业应用奠定基础。在该项目资助下，共发表学术论文34篇（均为SCI收录），其中SCI一区刊物7篇，Phys. Rev. B等SCI二区刊物8篇。学术交流和合作能力得到提升，学术影响力进一步增强。同时，培养硕博毕业研究生4名，一篇学位论文荣获福建省优秀学位论文，一名教师晋升教授、博士生导师，一名教师晋升副教授。