Chirality-Dependent Valley Polarization in Magnetic van der Waals Heterostructures via Spin-Selective Charge Transfer.

Magnetic proximity interaction provides a promising route to manipulate the spin and valley degrees of freedom in van der Waals heterostructures. Here, we report a control of valley pseudospin in the WS2/MoSe2 heterostructure by utilizing the magnetic proximity effect of few-layered CrBr3 and, for the first time, observe a substantial difference in valley polarization of intra/interlayer excitons under different circularly polarized laser excitations, referred to as chirality-dependent valley polarization. Theoretical and experimental results reveal that the spin-selective charge transfer between MoSe2 and CrBr3, as well as between MoSe2 and WS2, is mostly responsible for the chiral feature of valley polarization in comparison with the proximity exchange field. This means that a long-distance manipulation of exciton behaviors in multilayer heterostructures can be achieved through spin-selective charge transfer. This work marks a significant advancement in the control of spin and valley pseudospin in multilayer structures.

Room-Temperature Magneto-Photoresponse in All-2D Optoelectronic Devices for In-Sensor Vision Systems.

Interplay between magnetism and photoelectric properties introduces the effective control of photoresponse in optoelectronic devices via magnetic field, termed as magneto-photoresponse. It enriches the application scenarios and shows potential to construct in-sensor vision systems for artificial intelligence with gate-free architecture. However, achieving a simultaneous existence of room-temperature magnetism and notable photoelectric properties in semiconductors is a great challenge. Here, the room-temperature magneto-photoresponse is accomplished in all-2D optoelectronic devices, employing 2D ferromagnet Fe3GaTe2 as the source and drain, with WSe2 forming the channel. The interplay between room-temperature magnetism and photoelectric properties is realized by introducing the unique magneto-band structure effect from 2D interface, resulting in magneto-tunable charge transfer between Fe3GaTe2 and WSe2. The photocurrent in this 2D optoelectronic device exhibits robust response to both the direction and amplitude of external magnetic fields. Utilizing constructed 2D optoelectronic devices with magneto-photoresponse, traditional gate-controlled phototransistors are replaced and a prototype in-sensor vision system with visual adaptation, significantly improving the recognition accuracy to over four times in low-contrast environments is established. These findings pave a way for achieving high-temperature magneto-photoresponse, thereby guiding the construction of robust in-sensor vision systems toward high performance and broad applications.