Topological phases in quasi one-dimensional spin-1/2 systems

CLAUDIO GAZZA; NAIR AUCAR

Buenos Aires

Conferencia; Stat Phys 27 International Conference on Statistical Physics; 2019

In this work we study topological descriptions for different spin S=½ systems where there is a Haldane phase (corresponding to a one-dimensional S=1 spin chain) and there are different ways to frustrate this topological order. To analyse these systems we have used the tools proposed by Pollmann [1], based in observing the degeneracy of the entanglement spectrum.The main purpose of this work was to obtain the ground-state phases diagrams of spin ½ ladders with ferromagnetic interactions and two diagonal antiferromagnetic interactions that where regulated by a parameter. We have observed that there are three zones of interest in these diagrams. One corresponds to a ferromagnetic phase, another to a Haldane phase and between these phases there are a series of frustration-induced spin-gap phases with edge spins of different magnitudes [2]. Introducing another diagonal antiferromagnetic interaction, regulated with a parameter and using DMRG method we saw that there is a configuration in which the intermediate zone is bigger and might be easier to study the series of spin-gap phases.[1] F. Pollmann, A. M. Turner, E. Berg, and M. Oshikawa, Phys. Rev. B 81, 064439(2010).[2] K. Hida, J. Phys. Soc. Jpn. 85, 024705 (2016).