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# Field-tunable quantum disordered ground state in the triangular-lattice antiferromagnet NaYbO _{2}

## Abstract

Antiferromagnetically coupled S=1/2 spins on an isotropic triangular lattice is the paradigm of frustrated quantum magnetism, but structurally ideal realizations are rare. In this work, we investigate NaYbO _{2}, which hosts an ideal triangular lattice of J _{eff}=1/2 moments with no inherent site disorder. No signatures of conventional magnetic order appear down to 50 mK, strongly suggesting a quantum spin liquid ground state. We observe a two-peak specific heat and a nearly quadratic temperature dependence in accord with expectations for a two-dimensional Dirac spin liquid. Application of a magnetic field strongly perturbs the quantum disordered ground state and induces a clear transition into a collinear ordered state consistent with a long-predicted “up-up-down” structure for a triangular lattice XXZ Hamiltonian driven by quantum fluctuations. Moreover, the observation of spin liquid signatures in zero field and quantum-induced ordering in intermediate fields in the same compound demonstrate an intrinsically quantum disordered ground state. We conclude that NaYbO _{2} is a model, versatile platform for exploring spin liquid physics with full tunability of field and temperature.

- Authors:

- Univ. of California, Santa Barbara, CA (United States). Materials Dept.
- Boston College, Chestnut Hill, MA (United States). Dept. of Physics
- Univ. of California, Santa Barbara, CA (United States). Dept. of Physics
- Quantum Design, Inc., San Diego, CA (United States)
- Univ. of California, Santa Barbara, CA (United States). Dept. of Physics and Center for Terahertz Science and Technology
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Center for Neutron Research
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Center for Neutron Research; Univ. of Delaware, Newark, DE (United States). Dept. of Chemical and Biomolecular Engineering
- Univ. of California, Santa Barbara, CA (United States). Kavli Inst. for Theoretical Physics

- Publication Date:

- Research Org.:
- Univ. of California, Santa Barbara, CA (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; National Science Foundation (NSF)

- OSTI Identifier:
- 1574464

- Grant/Contract Number:
- SC0017752; FG02-08ER46524

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Nature Physics

- Additional Journal Information:
- Journal Volume: 15; Journal Issue: 10; Journal ID: ISSN 1745-2473

- Publisher:
- Nature Publishing Group (NPG)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; quantum spin liquid; neutron scattering; oxides; magnetism

### Citation Formats

```
Bordelon, Mitchell M., Kenney, Eric, Liu, Chunxiao, Hogan, Tom, Posthuma, Lorenzo, Kavand, Marzieh, Lyu, Yuanqi, Sherwin, Mark, Butch, N. P., Brown, Craig, Graf, M. J., Balents, Leon, and Wilson, Stephen D. Field-tunable quantum disordered ground state in the triangular-lattice antiferromagnet NaYbO2. United States: N. p., 2019.
Web. doi:10.1038/s41567-019-0594-5.
```

```
Bordelon, Mitchell M., Kenney, Eric, Liu, Chunxiao, Hogan, Tom, Posthuma, Lorenzo, Kavand, Marzieh, Lyu, Yuanqi, Sherwin, Mark, Butch, N. P., Brown, Craig, Graf, M. J., Balents, Leon, & Wilson, Stephen D. Field-tunable quantum disordered ground state in the triangular-lattice antiferromagnet NaYbO2. United States. doi:10.1038/s41567-019-0594-5.
```

```
Bordelon, Mitchell M., Kenney, Eric, Liu, Chunxiao, Hogan, Tom, Posthuma, Lorenzo, Kavand, Marzieh, Lyu, Yuanqi, Sherwin, Mark, Butch, N. P., Brown, Craig, Graf, M. J., Balents, Leon, and Wilson, Stephen D. Mon .
"Field-tunable quantum disordered ground state in the triangular-lattice antiferromagnet NaYbO2". United States. doi:10.1038/s41567-019-0594-5.
```

```
@article{osti_1574464,
```

title = {Field-tunable quantum disordered ground state in the triangular-lattice antiferromagnet NaYbO2},

author = {Bordelon, Mitchell M. and Kenney, Eric and Liu, Chunxiao and Hogan, Tom and Posthuma, Lorenzo and Kavand, Marzieh and Lyu, Yuanqi and Sherwin, Mark and Butch, N. P. and Brown, Craig and Graf, M. J. and Balents, Leon and Wilson, Stephen D.},

abstractNote = {Antiferromagnetically coupled S=1/2 spins on an isotropic triangular lattice is the paradigm of frustrated quantum magnetism, but structurally ideal realizations are rare. In this work, we investigate NaYbO2, which hosts an ideal triangular lattice of Jeff=1/2 moments with no inherent site disorder. No signatures of conventional magnetic order appear down to 50 mK, strongly suggesting a quantum spin liquid ground state. We observe a two-peak specific heat and a nearly quadratic temperature dependence in accord with expectations for a two-dimensional Dirac spin liquid. Application of a magnetic field strongly perturbs the quantum disordered ground state and induces a clear transition into a collinear ordered state consistent with a long-predicted “up-up-down” structure for a triangular lattice XXZ Hamiltonian driven by quantum fluctuations. Moreover, the observation of spin liquid signatures in zero field and quantum-induced ordering in intermediate fields in the same compound demonstrate an intrinsically quantum disordered ground state. We conclude that NaYbO2 is a model, versatile platform for exploring spin liquid physics with full tunability of field and temperature.},

doi = {10.1038/s41567-019-0594-5},

journal = {Nature Physics},

number = 10,

volume = 15,

place = {United States},

year = {2019},

month = {7}

}

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