Observation of Magnetic Proximity Effect Using Resonant Optical Spectroscopy of an Electrically Tunable MoSe2/CrBr3 Heterostructure

TLDR: The magnetic proximity effect allows us to use resonant optical spectroscopy to fully characterize the CrBr_{3} magnet, determining the easy-axis coercive field, the magnetic anisotropy energy, and critical exponents associated with spin susceptibility and magnetization.

Abstract: van der Waals heterostructures combining two-dimensional magnetic and semiconducting layers constitute a promising platform for interfacing magnetism, electronics, and optics. Here, we use resonant optical reflection spectroscopy to observe the magnetic proximity effect in a gate-tunable ${\mathrm{MoSe}}_{2}/{\mathrm{CrBr}}_{3}$ heterostructure. The high quality of the interface leads to a giant zero-field splitting of the $K$ and ${K}^{\ensuremath{'}}$ valley excitons in ${\mathrm{MoSe}}_{2}$, equivalent to an external magnetic field of 12 T, with a weak but distinct electric field dependence that hints at potential for electrical control of magnetization. The magnetic proximity effect allows us to use resonant optical spectroscopy to fully characterize the ${\mathrm{CrBr}}_{3}$ magnet, determining the easy-axis coercive field, the magnetic anisotropy energy, and critical exponents associated with spin susceptibility and magnetization.