skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Impact of disorder on dynamics and ordering in the honeycomb-lattice iridate Na 2 IrO 3

Abstract

Kitaev's honeycomb spin-liquid model and its proposed realization in materials such as α-RuCl3, Li 2IrO3, and Na2IrO3 continue to present open questions about how the dynamics of a spin liquid are modified in the presence of non-Kitaev interactions as well as the presence of inhomogeneities. Here we use 23Na nuclear magnetic resonance to probe both static and dynamical magnetic properties in single-crystal Na2IrO3 . We find that the NMR shift follows the bulk susceptibility above 30 K but deviates from it below; moreover below TN the spectra show a broad distribution of internal magnetic fields. Both of these results provide evidence for inequivalent magnetic sites at low temperature, suggesting inhomogeneities are important for the magnetism. The spin-lattice relaxation rate is isotropic and diverges at TN, suggesting that the Kitaev cubic axes may control the critical quantum spin fluctuations. Finally, in the ordered state, we observe gapless excitations, which may arise from site substitution, emergent defects from milder disorder, or possibly be associated with nearby quantum paramagnetic states distinct from the Kitaev spin liquid.

Authors:
ORCiD logo [1];  [2];  [3];  [3]; ORCiD logo [1];  [3];  [4]; ORCiD logo [2]
  1. Technical Univ. of Dresden, Dresden (Germany). Inst. of Solid State and Materials Physics
  2. Univ. of California, Davis, CA (United States). Dept. of Physics
  3. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Univ. of Colorado, Boulder, CO (United States); National Inst. of Standards and Technology (NIST), Boulder, CO (United States). JILA
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES); German Research Foundation (DFG); National Science Foundation (NSF)
OSTI Identifier:
1616111
Grant/Contract Number:  
AC02-05CH11231; DMR-1506961; DMR-1807889
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 101; Journal Issue: 8; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Sarkar, R., Mei, Z., Ruiz, A., Lopez, G., Klauss, H. -H., Analytis, J. G., Kimchi, I., and Curro, N. J. Impact of disorder on dynamics and ordering in the honeycomb-lattice iridate Na2IrO3. United States: N. p., 2020. Web. https://doi.org/10.1103/PhysRevB.101.081101.
Sarkar, R., Mei, Z., Ruiz, A., Lopez, G., Klauss, H. -H., Analytis, J. G., Kimchi, I., & Curro, N. J. Impact of disorder on dynamics and ordering in the honeycomb-lattice iridate Na2IrO3. United States. https://doi.org/10.1103/PhysRevB.101.081101
Sarkar, R., Mei, Z., Ruiz, A., Lopez, G., Klauss, H. -H., Analytis, J. G., Kimchi, I., and Curro, N. J. Mon . "Impact of disorder on dynamics and ordering in the honeycomb-lattice iridate Na2IrO3". United States. https://doi.org/10.1103/PhysRevB.101.081101. https://www.osti.gov/servlets/purl/1616111.
@article{osti_1616111,
title = {Impact of disorder on dynamics and ordering in the honeycomb-lattice iridate Na2IrO3},
author = {Sarkar, R. and Mei, Z. and Ruiz, A. and Lopez, G. and Klauss, H. -H. and Analytis, J. G. and Kimchi, I. and Curro, N. J.},
abstractNote = {Kitaev's honeycomb spin-liquid model and its proposed realization in materials such as α-RuCl3, Li 2IrO3, and Na2IrO3 continue to present open questions about how the dynamics of a spin liquid are modified in the presence of non-Kitaev interactions as well as the presence of inhomogeneities. Here we use 23Na nuclear magnetic resonance to probe both static and dynamical magnetic properties in single-crystal Na2IrO3 . We find that the NMR shift follows the bulk susceptibility above 30 K but deviates from it below; moreover below TN the spectra show a broad distribution of internal magnetic fields. Both of these results provide evidence for inequivalent magnetic sites at low temperature, suggesting inhomogeneities are important for the magnetism. The spin-lattice relaxation rate is isotropic and diverges at TN, suggesting that the Kitaev cubic axes may control the critical quantum spin fluctuations. Finally, in the ordered state, we observe gapless excitations, which may arise from site substitution, emergent defects from milder disorder, or possibly be associated with nearby quantum paramagnetic states distinct from the Kitaev spin liquid.},
doi = {10.1103/PhysRevB.101.081101},
journal = {Physical Review B},
number = 8,
volume = 101,
place = {United States},
year = {2020},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 1 work
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Zigzag Magnetic Order in the Iridium Oxide Na 2 IrO 3
journal, February 2013


Concept and realization of Kitaev quantum spin liquids
journal, March 2019

  • Takagi, Hidenori; Takayama, Tomohiro; Jackeli, George
  • Nature Reviews Physics, Vol. 1, Issue 4
  • DOI: 10.1038/s42254-019-0038-2

Dynamics of a Two-Dimensional Quantum Spin Liquid: Signatures of Emergent Majorana Fermions and Fluxes
journal, May 2014


Observation of two types of fractional excitation in the Kitaev honeycomb magnet
journal, May 2018


Physics of the Kitaev Model: Fractionalization, Dynamic Correlations, and Material Connections
journal, March 2018


Na 2 IrO 3 as a Novel Relativistic Mott Insulator with a 340-meV Gap
journal, December 2012


Chemical and hydrostatic-pressure effects on the Kitaev honeycomb material Na 2 IrO 3
journal, September 2018


Nuclear magnetic resonance in the heavy fermion superconductors
journal, January 2009


The Effect of Electron-Electron Interaction on the Nuclear Spin Relaxation in Metals
journal, April 1963

  • Moriya, Tôru
  • Journal of the Physical Society of Japan, Vol. 18, Issue 4
  • DOI: 10.1143/JPSJ.18.516

Local magnetic inhomogeneities in Ba ( Fe 1 x Ni x ) 2 As 2 as seen via A 75 s NMR
journal, October 2010


Local magnetism and spin dynamics of the frustrated honeycomb rhodate Li 2 RhO 3
journal, September 2017


Evidence for a Field-Induced Quantum Spin Liquid in α - RuCl 3
journal, July 2017


Relevance of the Heisenberg-Kitaev Model for the Honeycomb Lattice Iridates A 2 IrO 3
journal, March 2012


Spin Waves and Revised Crystal Structure of Honeycomb Iridate Na 2 IrO 3
journal, March 2012


Low-Energy Spin Dynamics of the Honeycomb Spin Liquid Beyond the Kitaev Limit
journal, July 2016


Nuclear magnetic resonance Knight shifts in the presence of strong spin–orbit and crystal-field potentials
journal, July 2016


Gapless Spin Excitations in the Field-Induced Quantum Spin Liquid Phase of α RuCl 3
journal, December 2017


Magnetic order and spin dynamics in La 2 O 2 Fe 2 OSe 2 probed by Fe 57 Mössbauer, La 139 NMR, and muon-spin relaxation spectroscopy
journal, November 2014


A spin–orbital-entangled quantum liquid on a honeycomb lattice
journal, February 2018

  • Kitagawa, K.; Takayama, T.; Matsumoto, Y.
  • Nature, Vol. 554, Issue 7692
  • DOI: 10.1038/nature25482

Scaling and data collapse from local moments in frustrated disordered quantum spin systems
journal, October 2018


Antiferromagnetic Mott insulating state in single crystals of the honeycomb lattice material Na 2 IrO 3
journal, August 2010


Nuclear Spin-Lattice Relaxation in Magnetic Insulators
journal, February 1968


Dynamics of fractionalization in quantum spin liquids
journal, September 2015


Kitaev matter
journal, May 2015

  • Gegenwart, Philipp; Trebst, Simon
  • Nature Physics, Vol. 11, Issue 6
  • DOI: 10.1038/nphys3346

Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
journal, January 2009


Valence Bonds in Random Quantum Magnets: Theory and Application to YbMgGaO 4
journal, July 2018


Direct evidence for dominant bond-directional interactions in a honeycomb lattice iridate Na2IrO3
journal, May 2015

  • Hwan Chun, Sae; Kim, Jong-Woo; Kim, Jungho
  • Nature Physics, Vol. 11, Issue 6
  • DOI: 10.1038/nphys3322

Long-range magnetic ordering in Na 2 IrO 3
journal, June 2011