Effects of field modulation on Aharonov-Bohm cages in a two-dimensional bipartite periodic lattice

Abstract

We study the effects of field modulation on the energy spectrum of an electron in a two-dimensional bipartite periodic lattice subject to a magnetic field. Dependence of the energy spectrum on both the period and the strength of field modulation is discussed in detail. Our main finding is that introducing field modulation drastically changes the energy spectrum and the localization properties of the system appearing in the absence of field modulation; the degeneracies induced by a uniform magnetic field are broken and the resultant energy spectrum shows a dispersive band structure, indicating that most of Aharonov-Bohm cages become unbounded. The effects of field modulation on the superconducting transition temperature and the critical current in a wire network with the same geometry are also discussed.