Characterization of Topological Phases of Spin-1/2 Frustrated Ferromagnetic-Antiferromagnetic Alternating Heisenberg Chains by Entanglement Spectrum

TL;DR

This paper confirms the topological classification of frustration-induced spin-gap phases in a spin-1/2 alternating Heisenberg chain using entanglement spectra and iDMRG, supporting the valence bond solid picture.

Contribution

It introduces a new entanglement spectrum analysis to classify topological phases in frustrated spin chains, validated by numerical iDMRG calculations.

Findings

Entanglement spectra confirm topological phases

Results align with valence bond solid theory

Numerical methods validate phase classification

Abstract

The topological classification of a series of frustration-induced spin-gap phases in the spin-1/2 ferromagnetic--antiferromagnetic alternating Heisenberg chain with next-nearest-neighbour interaction reported in J. Phys. Soc. Jpn. 82, 064703 (2013) is confirmed using two kinds of entanglement spectra defined by different divisions of the whole chain. For the numerical calculation, the iDMRG method is used. The results are consistent with the valence bond solid picture proposed in the previous paper.