Topological insulators and fractional quantum Hall effect on the ruby lattice

• DOI: 10.1103/physrevb.84.155116
• Publication Date: 2011-10-14T13:06:17Z
• Authors: Xiang Hu; Mehdi Kargarian; Gregory A. Fiete
• Keywords: Topological insulator; Lattice (music)

We study a tight-binding model on the two-dimensional ruby lattice. This lattice supports several types of first and second neighbor spin-dependent hopping parameters in an $s$-band that preserves time-reversal symmetry. discuss phase diagram this for various values filling fractions, note interesting competition between spin-orbit terms individually would drive system to $Z_2$ topological insulating phase. also closely related spin-polarized with only hoppings show extremely flat bands finite Chern numbers result, ratio band gap width approximately 70. Such are ideal platform realize fractional quantum Hall effect at appropriate fractions. The can be possibly engineered optical lattices, may open door studies transitions spin liquids, insulators, integer states.