Far out-of-equilibrium spin populations trigger giant spin injection into atomically thin MoS2

被引:132
作者
Cheng, Liang [1 ]
Wang, Xinbo [1 ,2 ,3 ]
Yang, Weifeng [4 ]
Chai, Jianwei [4 ]
Yang, Ming [4 ]
Chen, Mengji [5 ]
Wu, Yang [5 ]
Chen, Xiaoxuan [1 ]
Chi, Dongzhi [4 ]
Goh, Kuan Eng Johnson [4 ]
Zhu, Jian-Xin [6 ,7 ]
Sun, Handong [1 ]
Wang, Shijie [4 ]
Song, Justin C. W. [1 ,8 ]
Battiato, Marco [1 ,9 ]
Yang, Hyunsoo [5 ]
Chia, Elbert E. M. [1 ]
机构
[1] Nanyang Technol Univ, Sch Phys & Math Sci, Div Phys & Appl Phys, Singapore, Singapore
[2] Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Beijing, Peoples R China
[3] Chinese Acad Sci, Inst Phys, Beijing, Peoples R China
[4] ASTAR, Inst Mat Res & Engn, Singapore, Singapore
[5] Natl Univ Singapore, Dept Elect & Comp Engn, Singapore, Singapore
[6] Los Alamos Natl Lab, Theoret Div, Los Alamos, NM USA
[7] Los Alamos Natl Lab, Ctr Integrated Nanotechnol, Los Alamos, NM USA
[8] ASTAR, Inst High Performance Comp, Singapore, Singapore
[9] Vienna Univ Technol, Inst Solid State Phys, Vienna, Austria
基金
奥地利科学基金会; 新加坡国家研究基金会;
关键词
TRANSPORT; SILICON; CHALLENGES; MONOLAYER; EMITTERS; SURFACE; METAL;
D O I
10.1038/s41567-018-0406-3
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Injecting spins from ferromagnetic metals into semiconductors efficiently is a crucial step towards the seamless integration of charge- and spin-information processing in a single device(1,2). However, efficient spin injection into semiconductors has remained an elusive challenge even after almost three decades of major scientific effort(3-5), due to, for example, the extremely low injection efficiencies originating from impedance mismatch(1,2,5,6), or technological challenges originating from stability and the costs of the approaches(7-12). We show here that, by utilizing the strongly out-of-equilibrium nature of subpicosecond spin-current pulses, we can obtain a massive spin transfer even across a bare ferromagnet/semi-conductor interface. We demonstrate this by producing ultra-short spin-polarized current pulses in Co and injecting them into monolayer MoS2, a two-dimensional semiconductor. The MoS2 layer acts both as the receiver of the spin injection and as a selective converter of the spin current into a charge current, whose terahertz emission is then measured. Strikingly, we measure a giant spin current, orders of magnitude larger than typical injected spin-current densities using currently available techniques. Our result demonstrates that technologically relevant spin currents do not require the very strong excitations typically associated with femtosecond lasers. Rather, they can be driven by ultralow-intensity laser pulses, finally enabling ultrashort spin-current pulses to be a technologically viable information carrier for terahertz spintronics.
引用
收藏
页码:347 / +
页数:6
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