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arXiv:2406.01760 · Physical review. B./Physical review. B

Phase diagram and topology of the XXZ chain with alternating bonds and staggered magnetic field

B. F. Márquez, N. Aucar Boidi, K. Hallberg, Armando A. Aligia

Published Jun 21, 2024• 7 citations
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Abstract

The XXZ spin-half chain has Heisenberg exchange interactions ${J}_{z}$ $({J}_{\ensuremath{\perp}})$ in the $z$ $(x,y)$ direction. The model has a transition from the spin-fluid phase for $\ensuremath{-}{J}_{\ensuremath{\perp}}<{J}_{z}<{J}_{\ensuremath{\perp}}$ to the N\'eel phase for ${J}_{z}>{J}_{\ensuremath{\perp}}>0$. When bond alternation $\ensuremath{\delta}$ is included, the N\'eel phase transitions to the dimer phase for a finite value of $\ensuremath{\delta}$. We determine the phase diagram using simple topological indicators related to the polarization of both spins. When a staggered magnetic field $B$ is included, a contour plot of these indicators as a function of $\ensuremath{\delta}$ and $B$ determine the amount of topological quantized spin pumping around closed circuits in the $(\ensuremath{\delta},B)$ plane.

DOI
10.1103/physrevb.109.235143

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Phases and phase transitions in a dimerized spin-12\mathbf{\frac{1}{2}}21​ XXZ chain
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