Rearrangement of uncorrelated valence bonds evidenced by low-energy spin excitations in YbMgGaO4
| Autor: | Sebastian Bachus, Alexandre Bertin, Yoshifumi Tokiwa, Philipp Gegenwart, Astrid Schneidewind, Yuesheng Li, Benqiong Liu, Igor Radelytskyi, Alexander A. Tsirlin |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics
Condensed Matter - Materials Science Strongly Correlated Electrons (cond-mat.str-el) Spins Condensed matter physics Condensed Matter - Superconductivity Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences General Physics and Astronomy engineering.material 01 natural sciences Magnetic susceptibility Inelastic neutron scattering Superconductivity (cond-mat.supr-con) Condensed Matter - Strongly Correlated Electrons Lattice (order) 0103 physical sciences engineering ddc:530 Herbertsmithite Valence bond theory Condensed Matter::Strongly Correlated Electrons 010306 general physics Spin (physics) Excitation |
| Zdroj: | Physical review letters 122(13), 137201 (2019). doi:10.1103/PhysRevLett.122.137201 |
| DOI: | 10.1103/PhysRevLett.122.137201 |
| Popis: | DC-magnetization data measured down to 40 mK speak against conventional freezing and reinstate YbMgGaO$_4$ as a triangular spin-liquid candidate. Magnetic susceptibility measured parallel and perpendicular to the $c$-axis reaches constant values below 0.1 and 0.2 K, respectively, thus indicating the presence of gapless low-energy spin excitations. We elucidate their nature in the triple-axis inelastic neutron scattering experiment that pinpoints the low-energy ($E$ $\leq$ $J_0$ $\sim$ 0.2 meV) part of the excitation continuum present at low temperatures ($T$ $$ $J_0$ that is rooted in the breaking of nearest-neighbor valence bonds and persists to temperatures well above $J_0$/$k_B$, the low-energy one originates from the rearrangement of the valence bonds and thus from the propagation of unpaired spins. We further extend this picture to herbertsmithite, the spin-liquid candidate on the kagome lattice, and argue that such a hierarchy of magnetic excitations may be a universal feature of quantum spin liquids. Comment: accepted in Phys. Rev. Lett |
| Databáze: | OpenAIRE |
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