Abstract
The nature of symmetry-protected topological phases of Heisenberg spin chains in totally symmetric representations of rank of the ) group is investigated through a Majorana fermion study starting from an integrable point. The latter approach generalizes the one pioneered by Tsvelik [Phys. Rev. B 42, 10499 (1990)] to describe the low-energy properties of the Haldane phase of the spin-1 Heisenberg chain from three massive Majorana fermions. We find, for all 's, the emergence of a nondegenerate gapped phase with edge states whose topological protection depends on the parity of . Whereas for odd, there is no such protection, the phase with even is shown to be topologically protected. We find that the phase belongs to the same topological class as the phase with edge states living in self-conjugate fully antisymmetric representation of the group.
- Received 5 July 2020
- Accepted 18 August 2020
DOI:https://doi.org/10.1103/PhysRevB.102.094410
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