Spin photovoltaic effect in magnetic van der Waals heterostructures

The development of van der Waals (vdW) crystals and their heterostructures has created a fascinating platform for exploring optoelectronic properties in the two-dimensional (2D) limit. With the recent discovery of 2D magnets, the control of the spin degree of freedom can be integrated to realize 2D spin-optoelectronics. Here, we report spin photovoltaic effects in vdW heterostructures of 2D magnet chromium triiodide (CrI3) sandwiched by graphene contacts. The photocurrent displays a distinct dependence on light helicity, which can be tuned by varying the magnetic states and photon energy. Circular polarization-resolved absorption measurements reveal that these observations originate from magnetic order-coupled and, thus, helicity-dependent charge-transfer excitons. The photocurrent displays multiple plateaus as the magnetic field is swept, associated with different CrI3 spin configurations. Giant photo-magnetocurrent is observed, which tends to infinity for a small applied bias. Our results pave the way to explore emergent photospintronics by engineering magnetic vdW heterostructures.