Unconventional Field-Induced Spin Gap in an S=1/2 Chiral Staggered Chain

Liu, J.; Kittaka, S.; Johnson, R. D.; Lancaster, T.; Singleton, J.; Sakakibara, T.; Kohama, Y.; van Tol, J.; Ardavan, A.; Williams, B. H.; Blundell, S. J.; Manson, Z. E.; Manson, J. L.; Goddard, P. A.

doi:10.1103/physrevlett.122.057207

Unconventional Field-Induced Spin Gap in an S=1/2 Chiral Staggered Chain

Liu, J.; Kittaka, S.; Johnson, R. D.; Lancaster, T.; Singleton, J.; Sakakibara, T.; Kohama, Y.; van Tol, J.; Ardavan, A.; Williams, B. H.; Blundell, S. J.; Manson, Z. E.; Manson, J. L.; Goddard, P. A.

Authors

J. Liu

S. Kittaka

R. D. Johnson

Professor Tom Lancaster tom.lancaster@durham.ac.uk
Professor

J. Singleton

T. Sakakibara

Y. Kohama

J. van Tol

A. Ardavan

B. H. Williams

S. J. Blundell

Z. E. Manson

J. L. Manson

P. A. Goddard

Abstract

We investigate the low-temperature magnetic properties of the molecule-based chiral spin chain ½CuðpymÞðH2OÞ4SiF6 · H2O (pym ¼ pyrimidine). Electron-spin resonance, magnetometry and heat capacity measurements reveal the presence of staggered g tensors, a rich low-temperature excitation spectrum, a staggered susceptibility, and a spin gap that opens on the application of a magnetic field. These phenomena are reminiscent of those previously observed in nonchiral staggered chains, which are explicable within the sine-Gordon quantum-field theory. In the present case, however, although the sineGordon model accounts well for the form of the temperature dependence of the heat capacity, the size of the gap and its measured linear field dependence do not fit with the sine-Gordon theory as it stands. We propose that the differences arise due to additional terms in the Hamiltonian resulting from the chiral structure of ½CuðpymÞðH2OÞ4SiF6 · H2O, particularly a uniform Dzyaloshinskii-Moriya coupling and a fourfold periodic staggered field.

Citation

Liu, J., Kittaka, S., Johnson, R., Lancaster, T., Singleton, J., Sakakibara, T., …Goddard, P. (2019). Unconventional Field-Induced Spin Gap in an S=1/2 Chiral Staggered Chain. Physical Review Letters, 122(5), Article 057207. https://doi.org/10.1103/physrevlett.122.057207

Journal Article Type	Article
Acceptance Date	Jan 4, 2019
Online Publication Date	Feb 8, 2019
Publication Date	Feb 8, 2019
Deposit Date	Feb 11, 2019
Publicly Available Date	Feb 12, 2019
Journal	Physical Review Letters
Print ISSN	0031-9007
Electronic ISSN	1079-7114
Publisher	American Physical Society
Peer Reviewed	Peer Reviewed
Volume	122
Issue	5
Article Number	057207
DOI	https://doi.org/10.1103/physrevlett.122.057207
Related Public URLs	https://arxiv.org/abs/1901.02292

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Copyright Statement
Reprinted with permission from the American Physical Society: Liu, J., Kittaka, S., Johnson, R. D., Lancaster, T., Singleton, J., Sakakibara, T., Kohama, Y., van Tol, J., Ardavan, A., Williams, B. H., Blundell, S. J., Manson, Z. E., Manson, J. L. & Goddard, P. A. (2019). Unconventional Field-Induced Spin Gap in an S=1/2Chiral Staggered Chain. Physical Review Letters 122(5): 057207 © 2019 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.