TY  - JOUR
AU  - Li, Yuesheng
AU  - Bachus, Sebastian
AU  - Liu, Benqiong
AU  - Radelytskyi, Igor
AU  - Bertin, Alexandre
AU  - Schneidewind, Astrid
AU  - Tokiwa, Yoshifumi
AU  - Tsirlin, Alexander A.
AU  - Gegenwart, Philipp
TI  - Rearrangement of Uncorrelated Valence Bonds Evidenced by Low-Energy Spin Excitations in YbMgGaO 4
JO  - Physical review letters
VL  - 122
IS  - 13
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2019-02804
SP  - 137201
PY  - 2019
AB  - 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.
LB  - PUB:(DE-HGF)16
C6  - pmid:31012603
UR  - <Go to ISI:>//WOS:000463901800015
DO  - DOI:10.1103/PhysRevLett.122.137201
UR  - https://juser.fz-juelich.de/record/862498
ER  -