Figure 2. MSHG-RA patterns of the EuS–Bi₂Se₃ heterostructures.

(a,d) Experimental set-up of the MSHG-RA measurements. Magnitude of SHG was measured as a function of input polarization angle while an (a) in-plane or an (d) out-of-plane magnetic field was applied to the sample. A set of a half-wave plate and a polarizer was rotated simultaneously so that the output SHG polarization was set to be either parallel or perpendicular to the input polarization. Only the parallel polarization measurements are shown here. (b) SHG Intensity as a function of input polarization angle from a 7 nm (EuS)–7 QL (Bi₂Se₃) sample. In-plane magnetic fields of +300 (orange) and −300 Oe (purple) were applied to the sample at 4 K. (c) An enlarged plot of the rectangular area in b. (e) The same plot as b but out-of-plane magnetic fields of +4,000 (orange) and −4000 Oe (purple) were applied to the sample. A small rotation of the MSHG-RA pattern is observed in f, which is an enlarged plot of the rectangular area in e. In b and e magnetic field directions are denoted by the orange and purple arrows, dots and crosses.