SciPost Phys. Core 5, 048 (2022) ·
published 10 October 2022
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Topological crystalline insulators are phases of matter where the crystalline
symmetries solely protect the topology. In this work, we explore the effect of
many-body interactions in a subclass of topological crystalline insulators,
namely the mirror-symmetry protected topological crystalline insulator.
Employing a prototypical mirror-symmetric quasi-one-dimensional model, we
demonstrate the emergence of a mirror-symmetry protected topological phase and
its robustness in the presence of short-range interactions. When longer-range
interactions are introduced, we find an interaction-induced topological phase
transition between the mirror-symmetry protected topological order and a
trivial charge density wave. The results are obtained using density-matrix
renormalization group and quantum Monte-Carlo simulations in applicable limits.
SciPost Phys. 10, 059 (2021) ·
published 9 March 2021
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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.
