Two-dimensional bipolar magnetic semiconductors with high Curie-temperature and electrically controllable spin polarization realized in exfoliated Cr(pyrazine)2 monolayers

• 作者: Xiangyang Li Haifeng Lv Xiaofeng Liu Tong Jin Xiaojun Wu Xingxing Li Jinlong Yang
• 来源期刊: 中国科学：化学（英文版）
• 年，卷（期）: 2021,（12）
• 所属期刊栏目: ARTICLES
• 页码范围: 2212-2217
• 页数: 6页
• 语种: 英文

摘要

Exploring two-dimensional (2D) magnetic semiconductors with room-temperature magnetic ordering and electrically controllable spin-polarization is a highly desirable but challenging task for nano-spintronics.Here,through first-principles calculations,we propose to realize such a material by exfoliating the recently synthesized organometallic layered crystal Li0.7[Cr(pyz)2]Cl0.7·0.25(THF) (pyz=pyrazine,THF=tetrahydrofuran).The feasibility of exfoliation is confirmed by the rather low exfoliation energy of 0.27 J m-2,even smaller than that of graphite.In exfoliated Cr(pyz)2 monolayers,each pyrazine ring grabs one electron from the Cr atom to become a radical anion,and then a strong d-p direct-exchange magnetic interaction emerges between Cr cations and pyrazine radicals,resulting in room-temperature ferrimagnetism with a Curie temperature of 342 K.Moreover,the Cr(pyz)2 monolayer is revealed to be an intrinsic bipolar magnetic semiconductor where electrical doping can induce half-metallic conduction with controllable spin-polarization direction.