AI Article Synopsis
- The paper proposes a method to flatten isolated Bloch bands with nonzero Chern numbers using specific tuning of hopping ratios in two models: the Haldane model and the chiral-π-flux square lattice model.
- It demonstrates that perfect band flattening can be achieved by introducing longer-range hopping that decreases with distance.
- Additionally, the study incorporates interactions and shows through exact diagonalization that this leads to a spectral gap, a topological ground state, and quantized Hall conductance in a system at 1/3 filling.
Article Abstract
We present a simple prescription to flatten isolated Bloch bands with a nonzero Chern number. We first show that approximate flattening of bands with a nonzero Chern number is possible by tuning ratios of nearest-neighbor and next-nearest-neighbor hoppings in the Haldane model and, similarly, in the chiral-π-flux square lattice model. Then we show that perfect flattening can be attained with further range hoppings that decrease exponentially with distance. Finally, we add interactions to the model and present exact diagonalization results for a small system at 1/3 filling that support (i) the existence of a spectral gap, (ii) that the ground state is a topological state, and (iii) that the Hall conductance is quantized.
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| http://dx.doi.org/10.1103/PhysRevLett.106.236804 | DOI Listing |
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