- Emergence of spin singlets with inhomogeneous gaps in the kagome lattice Heisenberg antiferromagnets Zn-barlowite and herbertsmithite NATURE PHYSICS 2021
- Site-specific structure at multiple length scales in kagome quantum spin liquid candidates PHYSICAL REVIEW MATERIALS 2020; 4 (12)
- Materializing rival ground states in the barlowite family of kagome magnets: quantum spin liquid, spin ordered, and valence bond crystal states NPJ QUANTUM MATERIALS 2020; 5 (1)
Site-Specific Structure at Multiple Length Scales in Kagome Quantum Spin Liquid Candidates.
Physical review materials
2020; 4 (12)
Realizing a quantum spin liquid (QSL) ground state in a real material is a leading issue in condensed matter physics research. In this pursuit, it is crucial to fully characterize the structure and influence of defects, as these can significantly affect the fragile QSL physics. Here, we perform a variety of cutting-edge synchrotron X-ray scattering and spectroscopy techniques, and we advance new methodologies for site-specific diffraction and L-edge Zn absorption spectroscopy. The experimental results along with our first-principles calculations address outstanding questions about the local and long-range structures of the two leading kagome QSL candidates, Zn-substituted barlowite (Cu3Zn x Cu1-x (OH)6FBr) and herbertsmithite (Cu3Zn(OH)6Cl2). On all length scales probed, there is no evidence that Zn substitutes onto the kagome layers, thereby preserving the QSL physics of the kagome lattice. Our calculations show that antisite disorder is not energetically favorable and is even less favorable in Zn-barlowite compared to herbertsmithite. Site-specific X-ray diffraction measurements of Zn-barlowite reveal that Cu2+ and Zn2+ selectively occupy distinct interlayer sites, in contrast to herbertsmithite. Using the first measured Zn L-edge inelastic X-ray absorption spectra combined with calculations, we discover a systematic correlation between the loss of inversion symmetry from pseudo-octahedral (herbertsmithite) to trigonal prismatic coordination (Zn-barlowite) with the emergence of a new peak. Overall, our measurements suggest that Zn-barlowite has structural advantages over herbertsmithite that make its magnetic properties closer to an ideal QSL candidate: its kagome layers are highly resistant to nonmagnetic defects while the interlayers can accommodate a higher amount of Zn substitution.
View details for DOI 10.1103/physrevmaterials.4.124406
View details for PubMedID 34095744
View details for PubMedCentralID PMC8174140
- Enhancement and destruction of spin-Peierls physics in a one-dimensional quantum magnet under pressure PHYSICAL REVIEW B 2018; 97 (5)
Synthesis dependent properties of barlowite and Zn-substituted barlowite
Journal of Solid State Chemistry
2018; 268: 123-129
View details for DOI 10.1016/j.jssc.2018.08.016