单层锗烷纳米材料中电子自旋相关性质调控机理的理论研究

Germanane semiconducting nanomaterial is the promising candidate to be served as the germanium-based spintronic nanodevice due to its novel properties such as long time spin relaxation and high charge mobility. Therefore, the subject of effective tuning the spin-dependent fundamental properties and electronic transport properties is emerging as the key issue and is crucial for the practical applications of nanodevices in the field of spintronics. This project proposes a computational strategy, on the basis of latest experimental achievements, to make single-layer germanane based material functioned as the components for spintronic devices. To effectively modulate the spin-dependent electronic states in the germanane naomaterial, we will make use of microstructure decoration constructed by the combination of heteroatom and vacancies. Consequently, the effect of heteroatom and vacancies on the spin-dependent electron transport properties is becoming one of the most important issues in the scope of theoretical physics to be addressed. Our theoretical study will be carried out to explore the fundamental understanding of the intrinsic physical mechanism of the microstructure consisting of heteroatom and vacancies on the spin-dependent electronic states of the covalently functionalized single-layer germanane nanomaterial, as implemented in the framework of density functional theory in combination with non-equilibrium Green's function. The above theoretical method for performance simulation will be further developed and improved with the support of this project, which could be helpful to the accurate prediction of spin-dependent quantities of stable single-layer germanane nanomaterial with covalent functionalization. Our theoretical studies are expected to result in the establishment of a parameter system referred to the spin-dependent electron transport properties that can be effectively modulated in terms of introducing heteroatom and vacancies that are integrated into microstructured decoration, which is of great significance and able to provide theoretical fundamentals for the fabrication and application of germanium-based nanodevices for spintronics.

锗烷半导体纳米材料以其长自旋弛豫时间和高电子迁移率等特点成为锗基自旋电子器件的理想材料，其自旋电子态基本性质和自旋输运特性的有效调控遂成为自旋电子器件实用化的关键课题。根据最新的锗烷制备实验研究结果，本项目提出了基于单层锗烷纳米材料的自旋电子器件设计方案，运用异质原子/空位缺陷相结合的手段对材料进行微结构修饰来更加有效地调控其自旋电子学基本性质。因此，异质原子/空位缺陷对锗烷自旋电子输运特性影响的物理机制成为亟待解决的理论研究课题。本项目拟采用密度泛函理论与非平衡格林函数相结合的理论研究方法，探索含有异质原子/空位缺陷的复合微结构共价功能化修饰对单层锗烷材料自旋电子学基本性质的调控的内在物理机制，进一步发展单层锗烷纳米材料电子自旋相关特性的性能预测方法，确立异质原子/空位缺陷修饰的参数控制体系，实现对材料自旋输运相关敏感物理量的有效调控，为将来锗基自旋电子器件的制造与应用提供理论参考。

以二维锗烯层状材料为基础的纳米自旋电子学的研究近年来吸引了较多关注。二维单层锗基晶体材料及其一维纳米带在低维纳米光电器件方面具有极其重要的潜在应用价值。本项目主要探讨了吸附原子和空位缺陷对二维锗基层状纳米材料自旋电子态的调控，研究了二维锗烷和锗烷纳米带的结构性质、电学性质、光学性质和输运性质，并分析了锗烷基纳米材料自旋输运特性的物理机制。研究发现二维锗烷纳米材料中的单氢脱附确实可以引入局域在锗原子上的磁矩，并赋予材料铁磁性；氢原子脱附和锗原子掺杂分别可引起吸收光谱的红移和蓝移。锗烷纳米带的宽度可用来调控量子受限程度，进而可以采用控制样品宽度的方法来调控材料的能隙及电子输运，且二维锗烷材料具有各项异性的电子输运特性。探索了多空位缺陷对锗烷纳米带自旋电子学性质的影响，发现脱附掉氢原子的锗原子经过弛豫后更倾向于具有非磁的结构。同时，我们研究了锗基五元环材料的稳定性和电子结构基本特性，以及掺杂对体系电子结构的调控。对于二维砷基纳米材料电子结构与拓扑电子态研究，化学功能化能有效调控其几何结构从而构建新型拓扑绝缘体和有效光伏器件。本项目探索的锗烷基单层纳米材料的功能化设计方案，有望为层状纳米材料自旋电子学器件的设计与制造提供性能预测方法和理论设计方案。