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arXiv · 1007.2998

Searching for topological density wave insulators in multi-orbital square lattice systems

Bohm-Jung Yang·Hae-Young Kee
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Abstract

We study topological properties of density wave states with broken translational symmetry in two-dimensional multi-orbital systems with a particular focus on t$_{2g}$ orbitals in square lattice. Due to distinct symmetry properties of d-orbitals, a nodal charge or spin density wave state with Dirac points protected by lattice symmetries can be achieved. When an additional order parameter with opposite reflection symmetry is introduced to a nodal density wave state, the system can be fully gapped leading to a band insulator. Among those, topological density wave (TDW) insulators can be realized, when an effective staggered on-site potential generates a gap to a pair of Dirac points connected by the inversion symmetry which have the same topological winding numbers. We also present a mean-field phase diagram for various density wave states, and discuss experimental implications of our results.

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Bohm-Jung Yang, Hae-Young Kee. 2010-07-18. Searching for topological density wave insulators in multi-orbital square lattice systems. https://doi.org/10.1103/physrevb.82.195126

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