Field-induced gap in the spin-1/2 antiferromagnetic Heisenberg chain: A density matrix renormalization group study

TL;DR

This study uses the density matrix renormalization group method to analyze the effects of uniform and staggered magnetic fields on the spin-1/2 antiferromagnetic Heisenberg chain, revealing field-induced gaps and incommensurate correlations.

Contribution

It extends previous research by systematically exploring the high magnetic field regime and the interplay of staggered and uniform fields in this model.

Findings

Reproduces experimental results on copper benzoate

Identifies new features at very high magnetic fields

Demonstrates incommensurate spin correlations

Abstract

We study the spin-1/2 antiferromagnetic Heisenberg chain in both uniform and (perpendicular) staggered magnetic fields using the density-matrix renormalization-group method. This model has been shown earlier to describe the physics of the copper benzoate materials in magnetic field. In the present work, we extend the study to more general case for a systematic investigation of the field-induced gap and related properties of the spin-1/2 antiferromagnetic Heisenberg chain. In particular, we explore the high magnetic field regime where interesting behaviors in the field-induced gap, magnetization, and spin correlation functions are found. Careful examination of the low energy properties and magnetization reveals interesting competing effects of the staggered and uniform fields. The incommensurate behavior in the spin correlation functions is demonstrated and discussed in detail. The present work reproduces earlier results in good agreement with experimental data on copper benzoate and predicts new interesting field-induced features at very high magnetic field.