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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Partial chiral symmetry-breaking as a route to spectrally isolated topological defect states in two-dimensional artificial materials
AU - Poli, Charles Joseph
AU - Schomerus, Henning Ulrich
AU - Bellec, Matthieu
AU - Kuhl, Ulrich
AU - Mortessagne, Fabrice
PY - 2017/6
Y1 - 2017/6
N2 - Bipartite quantum systems from the chiral universality classes admit topologically protected zero modes at point defects. However, in two-dimensional systems these states can be difficult to separate from compacton-like localized states that arise from flat bands, formed if the two sublattices support a different number of sites within a unit cell. Here we identify a natural reduction of chiral symmetry, obtained by coupling sites on the majority sublattice, which gives rise to spectrally isolated point-defect states, topologically characterized as zero modes supported by the complementary minority sublattice. We observe these states in a microwave realization of a dimerized Lieb lattice with next-nearest neighbour coupling, and also demonstrate topological mode selection via sublattice-staggered absorption.
AB - Bipartite quantum systems from the chiral universality classes admit topologically protected zero modes at point defects. However, in two-dimensional systems these states can be difficult to separate from compacton-like localized states that arise from flat bands, formed if the two sublattices support a different number of sites within a unit cell. Here we identify a natural reduction of chiral symmetry, obtained by coupling sites on the majority sublattice, which gives rise to spectrally isolated point-defect states, topologically characterized as zero modes supported by the complementary minority sublattice. We observe these states in a microwave realization of a dimerized Lieb lattice with next-nearest neighbour coupling, and also demonstrate topological mode selection via sublattice-staggered absorption.
KW - defect states
KW - topological materials
KW - symmetries
KW - mode selection
KW - flat bands
KW - Lieb lattice
KW - Dirac points
M3 - Journal article
VL - 4
JO - 2D Materials
JF - 2D Materials
SN - 2053-1583
IS - 2
M1 - 025008
ER -