Van der Waals heterostructures for spintronics and opto-spintronics

Giant valley splitting in a MoTe2/MnSe2 van der Waals heterostructure with room-temperature ferromagnetism

“…4,5 The feature of spin-valley locking provides broad ways to achieve valley polarization, such as optical pumping, [6][7][8][9] external magnetic field, 10,11 magnetic doping, [12][13][14][15] and forming vertical heterostructures with magnetic materials. [16][17][18][19][20][21][22][23][24][25][26] From the perspective of achieving large and stable valley splitting, none of the first three cases is the best choice because they are limited by the manipulating robustness, stability of the doped systems, and a tiny valley splitting efficiency (B0.2 meV T À1 ), 10,11 respectively, which are far from the requirements of practical applications. Conversely, realizing this goal via magnetic proximity effects between magnetic materials and TMDs, namely, forming TMD/magnetic material heterostructures, appears more promising.…”

“…Conversely, realizing this goal via magnetic proximity effects between magnetic materials and TMDs, namely, forming TMD/magnetic material heterostructures, appears more promising. 20,26 Before twodimensional (2D) magnets were successfully fabricated through experiments, 27,28 several notable examples of placing monolayer TMDs upon bulk (3D) magnetic substrates to form 2D/3D heterostructures, such as TMDs/EuO(EuS) 16,17 and n-WS 2 /p-(Ga,Mn)As, 29 have been utilized to manipulate valley splitting, in which a large substantial valley splitting of 44 meV was predicted theoretically in MoTe 2 /EuO [16], and a very recent experiment reported that the splitting efficiency in TMDs/EuS reached a value of 16 meV T À1 . 19 Additionally, to optimize the magnetic substrates, many 2Dmagnet/TMD vdW heterostructures have also been tried both experimentally and theoretically, such as CrI 3 /WSe 2 , 20,21 NiCl 2 / WTe 2 , 22 and h-VN/WS 2 , 23 where not only a considerable splitting size was obtained, but also the superiority of 2D/2D systems was verified.…”

Editorial: Optoelectronic Properties of Two-Dimensional Systems

“…The downscaling of electronic devices, in both size and energy consumption, passes through the improvement of fabrication techniques and the combination of 2D materials in van der Waals (vdW) heterostructures [1]. In recent years, more and more materials have been synthesized, whose very diverse properties have been analyzed with various techniques [2][3][4]. Stacking 2D materials together, and controlling the relative twist angle with an accuracy of less than a tenth of a degree [5], has opened an avenue for producing artificial materials with properties defined "on demand".…”

2D Bi2Se3 materials for optoelectronics

“…In the last decade, a wealth of 2D layered materials have been isolated from bulk crystals or been fabricated through bottom-up synthesis ( Cai et al., 2018 ; Fang et al., 2021 ; Han et al., 2019a , 2019b ; Li et al., 2017 ; Varoon et al., 2011 ; Wang et al., 2020a , 2020b ; Zhou et al., 2018 ). Their fundamental physical properties and demonstrative functional devices have been thoroughly studied ( Koppens et al., 2014 ; Sierra et al., 2021 ; Wang et al., 2019a , 2019b , 2019c , 2021a , 2021b , 2021c , 2021d )). These thereby vastly promote the application of 2D layered materials in next-generation advanced devices.…”