Heusler型自旋零能隙半导体材料的能带调控和新型合金设计制备

As a new family of spintronic materials, spin-gapless semiconductors (SGSs) have received considerable interest in the field of spintronics due to their excellent properties, such as low carrier concentration, high carrier mobility, and 100% spin polarization ratio. However, the theoretical prediction of SGSs is always rule-less and coincidence, and the predicted SGSs are not very stable. Therefore, the key scientific problems in the current field are to determine a new technical tool to control the zero-gap band structures of SGSs and to design more stable SGSs. Based on the earlier analysis from Heusler-type SGSs, by means of the first-principle calculations and the experimental measurements, we aim to focus on the half-metals, nearly half-metals and magnetic semiconductors, using doping effect to provide a new technical tool to tune the zero-gap band structures and to explain the origin of the band transitions and the zero-gap behaviors. Moreover, we aim to design nearly line dispersive SGSs, and discuss the mechanism of cubic-symmetry-protected direct zero-gap structures. Finally, on basis of these SGSs, we will design new hetero-junction and magnetic tunnels and study their physical and transport properties, which providing candidate materials and theoretical accumulation for next generation spintronics devices.

自旋零能隙半导体（SGS）是一类新型的自旋电子学材料，它具有100%的自旋极化率、高载流子迁移率和低载流子浓度等优异性能，是目前自旋电子学领域研究热点之一。然而，当前SGS的研究基本是随机、无规律的，且开发出的SGS不够稳定。因此，弄清SGS材料零能隙能带结构形成规律，建立有效调控其能带结构的方法，获得具有稳定结构的SGS，一直是该领域在国际上的难点问题。申请人拟在前期Heusler型SGS的研究基础上，采用理论和实验相结合的研究思路，通过对（近）半金属和磁性半导体材料进行微量元素替换，确定调控零能隙结构的技术手段，掌握其能带过渡和零能隙能带结构形成规律和调控机制。同时开发出具有准线性色散能带结构的SGS材料，阐明其（受立方对称性保护的）直接零能隙结构形成的物理起源，并构建基于SGS的异质结或磁隧道结器件，研究这些原理型器件的自旋电子输运特性，为下一代自旋电子学器件提供候选材料和理论积累。

(1) 申请人发现了CuMn2InSe4在理论上为良好的自旋零能隙半导体材料，并且通过不同的压力对其能带进行调控，成果发表于Journal of Alloys and Compounds 2019, 793, 302-313; (2) 申请人积极在Hesuler型材料中探索不同原子占位对能带的影响。系统的研究了all-d-metal新型Heusler材料Pd2CrZn 的原子占位，磁学特性和其Zn在电子结构和 磁学特性中的贡献，详细的理论研究将对后续的实验制备起到指导作用，成果发表于RSC Advances, 2020, 10, 17829-17835; (3) 申请人团队在菱形YbBO3中理论发 现了抛物线和线性色散共存的自旋零能隙半导体特性，并且研究了电子和空穴掺杂对其零能隙的调控, 成果发表于Journal of Alloys and Compounds 2020, 823, 153835；(4)申请人团队通过无序原子交换和应力对四元等比的Heusler材料TiZrMnAl的能带进行调控，成功预测了其完全补偿亚铁磁类型的自旋零能隙半导体的特性，成果发表于 Journal of Magnetism and Magnetic Materials, 2020, 508, 166880；（5）申请人还提出了节线型自旋零能隙半导体的概念，成果发表于Physics Reports, 2020, 888, 1-57; (6) 申请人对比了狄拉克自旋零能隙半导体和狄拉克半金 属的材料属性的异同，并且展望了狄拉克型自旋零能隙半导体材料在自旋电子学领域的潜在应用，成果发表于 Applied Physics Reviews, 2018, 5, 041103; (7) 申请人 团队理论开发多重狄拉克型自旋零能隙半导体PdF3并且基于 PdF3成功构建磁性隧 道结，系统的研究了其自旋输运特性，成果发表于Nanomaterials, 2019, 9, 1342; (8) 申请人将基于Heusler型自旋零能隙材料的性能研究进一步延伸到相关的器件应用 当中。研究成果发表于 Frontiers in Chemistry, 2019, 7, 550 .