Journal Article

FZJ-2025-03247

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Atacamite Cu$_2$Cl(OH)$_3$ in High Magnetic Fields: Quantum Criticality and Dimensional Reduction of a Sawtooth-Chain Compound

Heinze, L. (Corresponding author)FZJ* ; Kotte, T. ; Rausch, R. ; Demuer, A. ; Luther, S. ; Feyerherm, R. ; Ammerlaan, E. L. Q. N. ; Zeitler, U. ; Gorbunov, D. I. ; Uhlarz, M. ; Rule, K. C. ; Wolter, A. U. B. ; Kühne, H. ; Wosnitza, J. ; Karrasch, C. ; Süllow, S.

2025
APS College Park, Md.

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Please use a persistent id in citations: doi:10.1103/PhysRevLett.134.216701  doi:10.34734/FZJ-2025-03247

Abstract: We report an extensive high-field study of atacamite Cu$_2$⁢Cl⁢(OH)$_3$, a material realization of quantum sawtooth chains with weak interchain couplings, in continuous and pulsed magnetic fields up to 58 T. In particular, we have mapped the entropy landscape for fields as high as 35 T and have identified a field-induced quantum critical point at 21.9(1) T for H || c axis. The quantum critical point separates field regions with and without magnetic order, evidenced by our thermodynamic study and $^1$H nuclear magnetic resonance spectroscopy, but lies far below full saturation of the magnetization. Corroborated by numerical results using density-matrix renormalization group calculations, we find this behavior associated with a dimensional reduction of the spin system: the sawtooth chain effectively decouples into an antiferromagnetic spin-1/2 chain (backbone of the sawtooth chain) in the presence of an exchange field produced by the remaining field-polarized spins.

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

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Contributing Institute(s):

1. JCNS-4 (JCNS-4)
2. JCNS-3 (JCNS-3)
3. Heinz Maier-Leibnitz Zentrum (MLZ)
4. JCNS-FRM-II (JCNS-FRM-II)

Research Program(s):

1. 6G4 - Jülich Centre for Neutron Research (JCNS) (FZJ) (POF4-6G4) (POF4-6G4)
2. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2025

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; Nationallizenz ; SCOAP3 sponsored Journal ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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