Extended Data Fig. 1: Angle-resolved second-harmonic-generation (SHG).
From: Enhanced interactions of interlayer excitons in free-standing heterobilayers
The polarization-dependent SHG signal measured on the monolayer WSe2 (blue circles) and WS2 (red circles) regions of samples and the corresponding fittings (blue and red curves), which confirm the twist angles of 0 ± 0.5° (a), 3 ± 0.5° (b), 45 ± 0.5° (c) and 51 ± 0.5° (d), between WSe2 and WS2 layers. Samples in (a) and (b) are R-type stacked heterobilayers, which are confirmed by the enhanced SHG signal in experiments from WSe2/WS2 hetero-structure region comparing with the corresponding WSe2 and WS2 monolayer regions. Samples in (c) and (d) are H-type stacked heterobilayers, which are confirmed by the quenched SHG signal in experiments from WSe2/WS2 hetero-structure region comparing with the corresponding WSe2 and WS2 monolayer regions.
