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Microscopic theory of the nearest-neighbor valence bond sector of the spin-12 kagome antiferromagnet

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posted on 03.07.2018, 12:30 by Arnaud Ralko, Frederic Mila, Ioannis RousochatzakisIoannis Rousochatzakis
© 2018 American Physical Society. The spin-12 Heisenberg model on the kagome lattice, which is closely realized in layered Mott insulators such as ZnCu3(OH)6Cl2, is one of the oldest and most enigmatic spin-12 lattice models. While the numerical evidence has accumulated in favor of a quantum spin liquid, the debate is still open as to whether it is a Z2 spin liquid with very short-range correlations (some kind of resonating valence bond spin liquid), or an algebraic spin liquid with power-law correlations. To address this issue, we have pushed the program started by Rokhsar and Kivelson in their derivation of the effective quantum dimer model description of Heisenberg models to unprecedented accuracy for the spin-12 kagome, by including all the most important virtual singlet contributions on top of the orthogonalization of the nearest-neighbor valence bond singlet basis. Quite remarkably, the resulting picture is a competition between a Z2 spin liquid and a diamond valence bond crystal with a 12-site unit cell, as in the density-matrix renormalization group simulations of Yan et al. Furthermore, we found that, on cylinders of finite diameter d, there is a transition between the Z2 spin liquid at small d and the diamond valence bond crystal at large d, the prediction of the present microscopic description for the two-dimensional lattice. These results show that, if the ground state of the spin-12 kagome antiferromagnet can be described by nearest-neighbor singlet dimers, it is a diamond valence bond crystal, and, a contrario, that, if the system is a quantum spin liquid, it has to involve long-range singlets, consistent with the algebraic spin liquid scenario.

History

School

  • Science

Department

  • Physics

Published in

Physical Review B

Volume

97

Issue

10

Citation

RALKO, A., MILA, F. and ROUSOCHATZAKIS, I., 2018. Microscopic theory of the nearest-neighbor valence bond sector of the spin-12 kagome antiferromagnet. Physical Review B, 97: 104401.

Publisher

© American Physical Society

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

21/02/2018

Publication date

2018-03-01

Notes

This paper was accepted for publication in the journal Physical Review B and the definitive published version is available at https://doi.org/10.1103/PhysRevB.97.104401

ISSN

2469-9950

eISSN

2469-9969

Language

en

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