@article{ISI:000429929800004,
 abstract = {We study the phases of a spin system on the kagome lattice with
nearest-neighbor XXZ interactions with anisotropy ratio Delta and
Dzyaloshinskii-Moriya interactions with strength D. In the classical
limit where the spin S at each site is very large, we find a rich phase
diagram of the ground state as a function of Delta and D. There are five
distinct phases which correspond to different ground-state spin
configurations in the classical limit. We use spin-wave theory to find
the bulk energy bands of the magnons in some of these phases. We also
study a strip of the system which has infinite length and finite width;
we find states which are localized near one of the edges of the strip
with energies which lie in the gaps of the bulk states. In the
ferromagnetic phase in which all the spins point along the +(z)over-cap
or -(z)over-cap direction, the bulk bands are separated from each other
by finite energy gaps. This makes it possible to calculate the Berry
curvature at all momenta, and hence the Chern numbers for every band;
the number of edge states is related to the Chern numbers.
Interestingly, we find that there are four different regions in this
phase where the Chern numbers are different. Hence there are four
distinct topological phases even though the ground-state spin
configuration is identical in all these phases. We calculate the thermal
Hall conductivity of the magnons as a function of the temperature in the
above ferromagnetic phase; we find that this can distinguish between the
various topological phases. These results are valid for all values of S.
In the other phases, there are no gaps between the different bands;
hence the edge states are not topologically protected.},
 article-number = {134411},
 author = {Seshadri, Ranjani and Sen, Diptiman},
 doi = {10.1103/PhysRevB.97.134411},
 eissn = {2469-9969},
 issn = {2469-9950},
 journal = {PHYSICAL REVIEW B},
 month = {APR 13},
 number = {13},
 times-cited = {15},
 title = {Topological magnons in a kagome-lattice spin system with &ITXXZ&IT and
Dzyaloshinskii-Moriya interactions},
 unique-id = {ISI:000429929800004},
 volume = {97},
 year = {2018}
}