Edge states in Open Antiferromagnetic Heisenberg Chains

TL;DR

This study investigates edge effects in open antiferromagnetic Heisenberg chains with various spins using DMRG, confirming theoretical predictions about edge states in integer and half-integer spin chains.

Contribution

The paper provides numerical evidence for the existence and properties of edge states in open antiferromagnetic Heisenberg chains across different spin magnitudes, supporting theoretical models.

Findings

Integer spin chains have edge states with S_edge=S/2.

Half-integer spin chains show no edge states at S=1/2.

Edge states are present in S=3/2 chains with S_edge=1/2.

Abstract

In this letter we report our results in investigating edge effects of open antiferromagnetic Heisenberg spin chains with spin magnitudes $S=1/2, 1,3/2,2$ using the density-matrix renormalization group (DMRG) method initiated by White. For integer spin chains, we find that edge states with spin magnitude $S_{edge}=S/2$ exist, in agreement with Valence-Bond-Solid model picture. For half-integer spin chains, we find that no edge states exist for $S=1/2$ spin chain, but edge state exists in $S=3/2$ spin chain with $S_{edge}=1/2$, in agreement with previous conjecture by Ng. Strong finite size effects associated with spin dimmerization in half-integer spin chains will also be discussed.