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arXiv · 2010.16126

Weak topological insulating phases of hard-core-bosons on the honeycomb lattice

Amrita Ghosh·Eytan Grosfeld
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Abstract

We study the phases of hard-core-bosons on a two-dimensional periodic honeycomb lattice in the presence of an on-site potential with alternating sign along the different y-layers of the lattice. Using quantum Monte Carlo simulations supported by analytical calculations, we identify a weak topological insulator, characterized by a zero Chern number but non-zero Berry phase, which is manifested at either density 1/4 or 3/4, as determined by the potential pattern. Additionally, a charge-density-wave insulator is observed at 1/2-filling, whereas the phase diagram at intermediate densities is occupied by a superfluid phase. The weak topological insulator is further shown to be robust against any amount of nearest-neighbor repulsion, as well as weak next-nearest-neighbor repulsion. The experimental realization of our model is feasible in an optical lattice setup.

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Amrita Ghosh, Eytan Grosfeld. 2020-10-30. Weak topological insulating phases of hard-core-bosons on the honeycomb lattice. https://doi.org/10.21468/scipostphys.10.3.059

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