Fig. 2: The magneto-optoelectronic response in the monolayer CrI₃ device D1.

a I–V curves of the device with a down magnetized state under \({\sigma }^{+}\) excitation with various powers (from 0 to 40 μW) measured at μ₀H = 0 T (increased from −0.3 T). For identical bias, the light-on current (I_light) increases monotonically with the excitation power. b Excitation power-dependent photoresponsivities (R₊ and R₋) measured at V = 0.2 V under \({\sigma }^{+}\) (red) and \({\sigma }^{-}\) (black) excitations in the down magnetized state CrI₃. c Excitation power dependent photoresponsivity polarization \(\rho\) measured at μ₀H = 0 T. The \(\rho\) is independent of excitation power with average values of ~−6% (red dashed line) for the up state (red dots) and ~+6% (blue dashed line) for the down state (blue dots). d Photocurrents, measured at V = 0.15 V, versus the angle of the quarter-wave plate. The up (down) state CrI₃ exhibits a higher \({\sigma }^{-}\) (\({\sigma }^{+}\)) photocurrent. e Circularly excited photocurrents under various magnetic fields. The red (black) color denotes the \({\sigma }^{+}\) (\({\sigma }^{-}\)) excitation result. When μ₀H sweeps between ±0.3 T, the photocurrent behaviors are opposite for \({\sigma }^{+}\) and \({\sigma }^{-}\) excitation. f The photoresponsivity polarization \(\rho\) values and the reflective magnetic circular dichroism (RMCD) signals (the inset) at various μ₀H. When μ₀H sweeps between −0.3 and +0.3 T, \(\rho\) changes between 6 and −6%, and RMCD signal changes between −1 and +1%. The CrI₃ spin-flip transitions occur at ±0.1 T.