TY - JOUR
T1 - Evidence of a field-induced Berezinskii-Kosterlitz-Thouless scenario in a two-dimensional spin-dimer system
AU - Tutsch, U.
AU - Wolf, B.
AU - Wessel, S.
AU - Postulka, L.
AU - Tsui, Y.
AU - Jeschke, H. O.
AU - Opahle, I.
AU - Saha-Dasgupta, T.
AU - Valentí, R.
AU - Brühl, A.
AU - Remović-Langer, K.
AU - Kretz, T.
AU - Lerner, H. W.
AU - Wagner, M.
AU - Lang, M.
N1 - Funding Information:
This work was supported by the Deutsche Forschungsgemeinschaft through the Trans-regional Collaborative Research Center SFB/TR 49, the Forschergruppe FOR 1807 and the project DFG WE 3649/3-1. We thank JSC Jülich and JARA-HPC for the allocation of CPU time.
Publisher Copyright:
© 2014 Macmillan Publishers Limited. All rights reserved.
PY - 2014
Y1 - 2014
N2 - Two-dimensional (2D) systems with continuous symmetry lack conventional long-range order because of thermal fluctuations. Instead, as pointed out by Berezinskii, Kosterlitz and Thouless (BKT), 2D systems may exhibit so-called topological order driven by the binding of vortex-antivortex pairs. Signatures of the BKT mechanism have been observed in thin films, specially designed heterostructures, layered magnets and trapped atomic gases. Here we report on an alternative approach for studying BKT physics by using a chemically constructed multilayer magnet. The novelty of this approach is to use molecular-based pairs of spin S=1/2. ions, which, by the application of a magnetic field, provide a gas of magnetic excitations. On the basis of measurements of the magnetic susceptibility and specific heat on a so-designed material, combined with density functional theory and quantum Monte Carlo calculations, we conclude that these excitations have a distinct 2D character, consistent with a BKT scenario, implying the emergence of vortices and antivortices.
AB - Two-dimensional (2D) systems with continuous symmetry lack conventional long-range order because of thermal fluctuations. Instead, as pointed out by Berezinskii, Kosterlitz and Thouless (BKT), 2D systems may exhibit so-called topological order driven by the binding of vortex-antivortex pairs. Signatures of the BKT mechanism have been observed in thin films, specially designed heterostructures, layered magnets and trapped atomic gases. Here we report on an alternative approach for studying BKT physics by using a chemically constructed multilayer magnet. The novelty of this approach is to use molecular-based pairs of spin S=1/2. ions, which, by the application of a magnetic field, provide a gas of magnetic excitations. On the basis of measurements of the magnetic susceptibility and specific heat on a so-designed material, combined with density functional theory and quantum Monte Carlo calculations, we conclude that these excitations have a distinct 2D character, consistent with a BKT scenario, implying the emergence of vortices and antivortices.
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U2 - 10.1038/ncomms6169
DO - 10.1038/ncomms6169
M3 - Article
AN - SCOPUS:84923270692
VL - 5
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
M1 - 5169
ER -