Topological hierarchy matters — topological matters with superlattices of defects
He Jing1, Kou Su-Peng2, †,
       

The illustration of the gauge choice. Moving along the arrow (both blue arrow and red arrow), the fermion acquires a phase shift π/2. The accumulated phase encircling each triangular lattice plaquette anti-clockwise is π/2. From Ref. [17].