Spontaneous ferromagnetism and magnetoresistance hysteresis in Ge_(1–x)Sn_(x)alloys  

Ⅳ族半导体Ge_(1-x)Sn_(x)中的自发磁化及磁阻回滞现象

作　　者：Ben-Chuan Lin Xing-Guo Ye Nan Wang Cai-Xin Zhang Hui-Xiong Deng Jing-Zhi Fang Hao-Nan Cui Shuo Wang Jian Liu Zhongming Wei Dapeng Yu Zhi-Min Liao Chunlai Xue 林本川;叶兴国;王楠;张才鑫;邓惠雄;房景治;崔浩楠;王硕;刘剑;魏钟鸣;俞大鹏;廖志敏;薛春来(Shenzhen Institute for Quantum Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China;Guangdong Provincial Key Laboratory of Quantum Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China;State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics,School of Physics,Peking University,Beijing 100871,China;Institute of Semiconductors,Chinese Academy of Sciences,Beijing 100083,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]Shenzhen Institute for Quantum Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China [2]Guangdong Provincial Key Laboratory of Quantum Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China [3]State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics,School of Physics,Peking University,Beijing 100871,China [4]Institute of Semiconductors,Chinese Academy of Sciences,Beijing 100083,China [5]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science Bulletin》2021年第14期1375-1378,M0003,共5页科学通报（英文版）

基　　金：the Key-Area Research and Development Program of Guangdong Province(2020B0303060001,and 2018B030327001);the National Natural Science Foundation of China(61874109,61922077,12004158,and 12074162);the National Key Research and Development Program of China(2018YFB2200100,and 2020YFA0309300);Guangdong Provincial Key Laboratory(2019B121203002)。

摘　　要：Introducing ferromagnetism into non-magnetic systems without the participation of magnetic elements is promising for all-electric spintronic devices[1,2].Many approaches have been pursued,such as non-magnetic defects induced magnetization in layered materials[3–5]or the inversion symmetry breaking induced magnetization in magic-angle bilayer graphene[6–8],etc.However,these approaches have to tackle with the localization effects or the inevitable precise control of twist angle,which hinders the future application into large-scale spintronic information devices.Theorists also predicted that the spontaneous ferromagnetism could emerge in the quasi-2D crystals[9]like GaSe,but no experimental results have been reported.Here,we report the spontaneous ferromagnetism induced by van Hove singularity[9–13]in non-magnetic groupⅣGe_(1–x)Sn_(x)alloys grown by the molecular beam epitaxy(MBE)technique.Our findings experimentally open up an opportunity to realize spintronics in groupⅣsemiconductors.以硅基半导体为代表的Ⅳ族半导体在现代工业中扮演着举足轻重的作用.然而,Ⅳ族半导体因其缺乏非常强的交换相互作用难以产生铁磁序,从而限制了蓬勃发展的自旋电子学器件在Ⅳ族半导体领域的应用.本文通过分子束外延生长Ⅳ族半导体Ge_(1-x)Sn_(x),引入原子排列的无序效应,从而打破反演对称性,在实验上成功观测到了自发铁磁序的产生.通过低温输运测量,可以清晰观测到电阻的回滞现象.通过磁化特性测量,进一步可以观测到自发铁磁序对应的磁滞回线,从而清晰地证明了Ⅳ族半导体Ge_(1-x)Sn_(x)中自发铁磁序的存在.通过第一性原理计算,作者指出此自发铁磁序源于临近布里渊区中心的范霍夫奇点引起的自旋极化的半金属态(half-metallicity).该工作成功地在非磁性的Ⅳ族半导体中诱导出来自发铁磁序,对自旋电子学应用于Ⅳ族半导体进而和现行的硅基工业标准兼容具有重要意义.

关 键 词：半导体领域 自发磁化 分子束外延生长 反演对称性 磁化特性 原子排列 布里渊区 自旋电子学 

分 类 号：TN304[电子电信—物理电子学] O472[理学—半导体物理]