Two-dimensional (2D) materials often host quantum behaviors that are not immediately visible 
from their global structure but emerge from subtle local environments and symmetry conditions. 
In this talk, I will introduce several “secret features” of spins and topology that arise in 
centrosymmetric 2D systems—phenomena that remain hidden in conventional analysis yet play 
a crucial role in determining their electronic and functional properties. Local inversion asymmetry 
in layered quantum materials gives rise to hidden spin textures, producing layer-dependent spin 
responses even when the crystal as a whole is centrosymmetric. Topologically hidden states, 
where symmetry-protected nontrivial features do not appear in standard band structures but 
become evident through orbital- and symmetry-resolved examinations. I will show how stacking 
engineering in bilayers can uncover or suppress these hidden topological characteristics, enabling 
a controllable transition between trivial and topological phases.