Magnetic ground state of the Kitaev ${\mathrm{Na}}_{2}{\mathrm{Co}}_{2}{\mathrm{TeO}}_{6}$ spin liquid candidate

Letter
Open Access

Magnetic ground state of the Kitaev ${Na}_{2} {Co}_{2} {TeO}_{6}$ spin liquid candidate

Weiliang Yao, Yang Zhao, Yiming Qiu, Christian Balz, J. Ross Stewart, Jeffrey W. Lynn, and Yuan Li

Phys. Rev. Research 5, L022045 – Published 2 June 2023

Abstract

As a candidate Kitaev material, ${Na}_{2} {Co}_{2} {TeO}_{6}$ exhibits intriguing magnetism on a honeycomb lattice that is believed to be $C_{3}$ symmetric. Here we report a neutron diffraction study of high-quality single crystals under $a$ -axis magnetic fields. Our data support the less common notion of a magnetic ground state that corresponds to a triple- $q$ magnetic structure with $C_{3}$ symmetry, rather than the multidomain zigzag structure typically assumed in prototype Kitaev spin liquid candidates. In particular, we find that the field is unable to repopulate the supposed zigzag domains, where the only alternative explanation is that the domains are strongly pinned by hitherto unidentified structural reasons. If the triple- $q$ structure is correct, then this requires reevaluation of many candidate Kitaev materials. We also find that fields beyond about 10 Tesla suppress the long-range antiferromagnetic order, allowing magnetic behavior to emerge different from that expected for a spin liquid.

Received 11 December 2022
Revised 23 March 2023
Accepted 11 May 2023

DOI:https://doi.org/10.1103/PhysRevResearch.5.L022045

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Antiferromagnetism Frustrated magnetism Quantum spin liquid

Antiferromagnets Layered crystals

Neutron diffraction

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Weiliang Yao^1,*, Yang Zhao^2,3, Yiming Qiu ², Christian Balz⁴, J. Ross Stewart ⁴, Jeffrey W. Lynn ², and Yuan Li ^1,5,†

¹International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
²NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
³Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA
⁴ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
⁵Collaborative Innovation Center of Quantum Matter, Beijing 100871, China

^*weiliangyao@outlook.com; Present address: Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA.
^†yuan.li@pku.edu.cn

Article Text

Click to Expand

Supplemental Material

Click to Expand

References

Click to Expand

Issue

Vol. 5, Iss. 2 — June - August 2023

Subject Areas

Reuse & Permissions

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
(a) The zigzag magnetic structure and its orientational domains. (b) The triple- $q$ magnetic structure. The moments can be thought of as a vector sum of the three patterns in panel (a) extended over the whole lattice. When one or three of the $ZZ n$ components are reversed, the chirality is reversed (inset). (c) Temperature dependence of the $M_{1}$ (0.5, 0, 1) reflection in selected fields, where the long-range magnetic order is robust (see Fig. S3 in Ref. [71]). Solid curves are power-law fits to the data (see text). Inset shows the reciprocal lattice in our setting, where hexagons are boundaries of 2D Brillouin zones, and the shaded ( $H$ , 0, $L$ ) plane is perpendicular to the field (purple arrows). Empty circles are structural Brillouin zone centers. Filled circles are magnetic Bragg peaks at the M points, color coded with the zigzag domains in panel (a).
Reuse & Permissions
Figure 2
(a) Field evolution of magnetic Bragg peak $M_{1}$ (0.5, 0, 1) at 2 K, with the sample undergoing a series of field scans after zero-field cooling (ZFC, see text), as well as after field cooling (FC) in 10 T. (b) Field evolution of Bragg peak (1, 0, 1) at 2 K. In the virgin zero field state, the observed intensity is due to nuclear Bragg scattering, whereas the field-enhanced intensity is a measure of uniform magnetization. (c) Field evolution of magnetic Bragg peak $M_{2}$ (0, 0.5, 1) at 2 K. Measurements displayed in the main panels are performed at the maximum of the peak profiles displayed in the insets. Horizontal dashed lines in panels (a) and (c) indicate background level. Error bars indicate statistical uncertainty (1 s.d.).
Reuse & Permissions
Figure 3
[(a)–(c)] Elastic scattering in the ( $H$ , 0, $L$ ) plane measured at 0.1 K under the specified field conditions. (d) Line cuts through the data in panels (a)–(c) along $c^{*}$ at $H = 0.5$ . (e) $T$ dependence of the signal at $M_{1}$ (0.5, 0, 1) measured in zero field upon warming the sample, before and after field training. Black dotted curve illustrates expected $T$ dependence of the $M_{2}$ (0, 0.5, 1) and $M_{3}$ ( $- 0.5$ , 0.5, 1) signals after field training, if the triple- $q$ scenario is correct (see text).
Reuse & Permissions
Figure 4
(a) Schematic field-training processes under the zigzag (upper half) and triple- $q$ (lower half) scenarios. The 10-T state is approximated as fully spin polarized. Polygons are color coded with Figs. 1 and 1. Dashed lines are boundaries between “hidden” low-symmetry structural domains. Hatches indicate suppressed $c$ -axis correlations. [(b), (c)] Schematic stacking in the (supposed) ZZ1 domain before and after field training. Yellow arrows indicate randomly reversed layers. [(d), (e)] Schematic stacking in the triple- $q$ structure before and after field training, color coded after Fig. 1. Gray rhombuses in panels (b)–(e) indicate the structural primitive cell.
Reuse & Permissions

Physical Review Research

Magnetic ground state of the Kitaev Na2Co2TeO6 spin liquid candidate

Weiliang Yao, Yang Zhao, Yiming Qiu, Christian Balz, J. Ross Stewart, Jeffrey W. Lynn, and Yuan Li

Phys. Rev. Research 5, L022045 – Published 2 June 2023

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

Article Text

Supplemental Material

References

Issue

Subject Areas

Authorization Required

Other Options

Download & Share

Images

Figure 1

Figure 2

Figure 3

Figure 4

Reuse & Permissions

Log In

Search

Article Lookup

Paste a citation or DOI

Enter a citation

Magnetic ground state of the Kitaev ${Na}_{2} {Co}_{2} {TeO}_{6}$ spin liquid candidate