Left: typical HAADF-STEM images of the prepared heterostructure from cross-sectional views. The dashed lines indicate the boundaries of CrTe2/Bi2Te3 with Te cap and SiNx substrate. Scale bar: 20 nm. Right: EDX color maps of Si, N, Cr, Bi, and Te, respectively. Cr element is uniformly distributed in the CrTe2 film, without spreading to Bi2Te3 and SiNx layers.