Griset, Christian and Head, Shane and Alicea, Jason and Starykh, Oleg A. (2011) Deformed triangular lattice antiferromagnets in a magnetic field: Role of spatial anisotropy and Dzyaloshinskii-Moriya interactions. Physical Review B, 84 (24). Art. No. 245108 . ISSN 1098-0121 http://resolver.caltech.edu/CaltechAUTHORS:20120131-101458254
- Published Version
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20120131-101458254
Recent experiments on the anisotropic spin-1/2 triangular antiferromagnet Cs_2CuBr_4 have revealed a remarkably rich phase diagram in applied magnetic fields, consisting of an unexpectedly large number of ordered phases. Motivated by this finding, we study the role of three ingredients—spatial anisotropy, Dzyaloshinskii-Moriya interactions, and quantum fluctuations—on the magnetization process of a triangular antiferromagnet, coming from the semiclassical limit. The richness of the problem stems from two key facts: (1) the classical isotropic model with a magnetic field exhibits a large accidental ground-state degeneracy and (2) these three ingredients compete with one another and split this degeneracy in opposing ways. Using a variety of complementary approaches, including extensive Monte Carlo numerics, spin-wave theory, and an analysis of Bose-Einstein condensation of magnons at high fields, we find that their interplay gives rise to a complex phase diagram consisting of numerous incommensurate and commensurate phases. Our results shed light on the observed phase diagram for Cs_2CuBr_4 and suggest a number of future theoretical and experimental directions that will be useful for obtaining a complete understanding of this material's interesting phenomenology.
|Additional Information:||© 2011 American Physical Society. Received 7 July 2011; revised manuscript received 30 September 2011; published 12 December 2011. We would like to acknowledge helpful conversations and discussions with Leon Balents, Andrey Chubukov, Michel Gingras, Olexei Motrunich, Roderich Moessner, Gil Refael, Yasu Takano, and Mike Zhitomirsky. We are grateful to Yasu Takano for sharing unpublished experimental results with us. We thank the Center for High Performance Computing at the University of Utah for their generous computer time allocation in the initial stages of this project. This research was supported by the National Science Foundation through Grants DMR-0808842 (S.H. and O.A.S.), DMR-1055522 (J.A.), and DGE-0707460 (C.G.) as well as Victoria B. Rodgers and the Rose Hills foundation (C.G.).|
|Classification Code:||PACS: 75.10.Jm, 75.30.Ds, 75.50.Ee|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||01 Feb 2012 19:04|
|Last Modified:||26 Dec 2012 14:45|
Repository Staff Only: item control page