Journal Article

FZJ-2019-02804

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Rearrangement of Uncorrelated Valence Bonds Evidenced by Low-Energy Spin Excitations in YbMgGaO 4

Li, Y. (Corresponding author) ; Bachus, S. ; Liu, B.FZJ* ; Radelytskyi, I.FZJ* ; Bertin, A. ; Schneidewind, A.FZJ* ; Tokiwa, Y. ; Tsirlin, A. A. ; Gegenwart, P.

2019
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/22127  doi:10.1103/PhysRevLett.122.137201

Abstract: dc-magnetization data measured down to 40 mK speak against conventional freezing and reinstateYbMgGaO4as a triangular spin-liquid candidate. Magnetic susceptibility measured parallel andperpendicular to thecaxis reaches constant values below 0.1 and 0.2 K, respectively, thus indicatingthe presence of gapless low-energy spin excitations. We elucidate their nature in the triple-axis inelasticneutron scattering experiment that pinpoints the low-energy (E≤J0∼0.2meV) part of the excitationcontinuum present at low temperatures (T<J0=kB), butcompletelydisappearing upon warming thesystem aboveT≫J0=kB. In contrast to the high-energy part atE>J0that is rooted in the breaking ofnearest-neighbor valence bonds and persists to temperatures well aboveJ0=kB, the low-energy oneoriginates 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 arguethat such a hierarchy of magnetic excitations may be a universal feature of quantum spin liquids.

Keyword(s): Magnetic Materials (1st) ; Magnetism (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Streumethoden (JCNS-2)
3. Heinz Maier-Leibnitz Zentrum (MLZ)

Research Program(s):

1. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. PANDA: Cold three axes spectrometer (SR2)

Appears in the scientific report 2019

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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