Layer-resolved magnetic proximity effect in van der Waals heterostructures

• Published in: Nature nanotechnology Vol. 15; no. 3; pp. 187 - 191
• Main Authors: Zhong, Ding, Seyler, Kyle L., Linpeng, Xiayu, Wilson, Nathan P., Taniguchi, Takashi, Watanabe, Kenji, McGuire, Michael A., Fu, Kai-Mei C., Xiao, Di, Yao, Wang, Xu, Xiaodong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2020; Nature Publishing Group
• Subjects: 140/125; 639/766/119/1000/1018; 639/766/119/997; Antiferromagnetism; Charge transfer; Chemistry and Materials Science; Circular dichroism; Dichroism; Ferromagnetism; Heterostructures; Letter; Magnetic domains; Magnetic fields; Magnetic properties; magnetic properties and materials; Magnetic structure; Magnetism; Magnetization; MATERIALS SCIENCE; Monolayers; Nanotechnology; Nanotechnology and Microengineering; Proximity; Proximity effect (electricity); Two dimensional materials; Wave functions
• DOI: 10.1038/s41565-019-0629-1
• ISSN: 1748-3387; 1748-3395

Magnetic proximity effects are integral to manipulating spintronic 1 , 2 , superconducting 3 , 4 , excitonic 5 and topological phenomena 6 – 8 in heterostructures. These effects are highly sensitive to the interfacial electronic properties, such as electron wavefunction overlap and band alignment. The recent emergence of magnetic two-dimensional materials opens new possibilities for exploring proximity effects in van der Waals heterostructures 9 – 12 . In particular, atomically thin CrI 3 exhibits layered antiferromagnetism, in which adjacent ferromagnetic monolayers are antiferromagnetically coupled 9 . Here we report a layer-resolved magnetic proximity effect in heterostructures formed by monolayer WSe 2 and bi/trilayer CrI 3 . By controlling the individual layer magnetization in CrI 3 with a magnetic field, we show that the spin-dependent charge transfer between WSe 2 and CrI 3 is dominated by the interfacial CrI 3 layer, while the proximity exchange field is highly sensitive to the layered magnetic structure as a whole. In combination with reflective magnetic circular dichroism measurements, these properties allow the use of monolayer WSe 2 as a spatially sensitive magnetic sensor to map out layered antiferromagnetic domain structures at zero magnetic field as well as antiferromagnetic/ferromagnetic domains at finite magnetic fields. Our work reveals a way to control proximity effects and probe interfacial magnetic order via van der Waals engineering 13 . Controlling the individual layer magnetization in CrI 3 enables the observation of a layer-resolved magnetic proximity effect in WSe 2 /CrI 3 heterostructures.