Group Structure of Wilson Loops in 2D Models with 2- and 4-Band Energy Spectra

T. Supatashvili, M. Eliashvili, G. Tsitsishvili

We consider a tight-binding model defined by a matrix Hamiltonian over 2D Brillouin zone. Multiband energy spectrum gives rise to a non-Abelian gauge structure set by the Berry con…