Title: Emergence of topological Mott insulators in proximity of quadratic band touching points
Author(s):

	I. Mandal (Laboratory of Atomic And Solid State Physics, Cornell University, Ithaca, NY 14853, USA) ,
	S. Gemsheim (Fakultät Physik, Technische Universität Dresden, 01069 Dresden, Germany)

Recently, the field of strongly correlated electrons has begun an intense search for a correlation induced topological insulating phase. An example is the quadratic band touching point which arises in a checkerboard lattice at half-filling, and in the presence of interactions gives rise to topological Mott insulators. In this work, we perform a mean-field theory computation to show that such a system shows instability to topological insulating phases even away from half-filling (chemical potential μ = 0). The interaction parameters consist of on-site repulsion (U), nearest-neighbour repulsion (V), and a next-nearest-neighbour correlated hopping (t_c). The t_c interaction originates from strong Coulomb repulsion. By tuning the values of these parameters, we obtain a desired topological phase that spans the area around (V = 0, μ = 0), extending to regions with (V > 0, μ = 0) and (V > 0, μ > 0). This extends the realm of current experimental efforts to find these topological phases.

Key words: checkerboard, quadratic band touching points, topology, Mott insulator, d-density wave
PACS: 73.43.-f, 73.43.Nq, 71.10.Fd

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