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Updated: Aug 7, 2025
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Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
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Field-Tunable Berezinskii-Kosterlitz-Thouless Correlations in a Heisenberg Magnet
D Opherden1, M S J Tepaske2,3, F Bärtl1,4
1Hochfeld-Magnetlabor Dresden (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany.
Physical Review Letters
|March 10, 2023
Summary
Field-induced Berezinskii-Kosterlitz-Thouless (BKT) correlations were observed in a spin-1/2 Heisenberg material. Magnetic fields tune XY anisotropy, creating a BKT regime and influencing the magnetic phase diagram.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
- Materials Science
Background:
- Spin-1/2 Heisenberg materials exhibit complex magnetic behaviors.
- Berezinskii-Kosterlitz-Thouless (BKT) theory describes 2D phase transitions.
- Understanding field effects on magnetic correlations is crucial.
Purpose of the Study:
- To investigate field-induced BKT correlations in [Cu(pz)2(2-HOpy)2](PF6)2.
- To explore the role of XY anisotropy and interlayer exchange on magnetic ordering.
- To elucidate the nonmonotonic magnetic phase diagram.
Main Methods:
- Nuclear magnetic resonance (NMR) measurements to probe spin correlations.
- Stochastic series expansion quantum Monte Carlo simulations.
- Finite-size scaling analysis of in-plane spin stiffness.
Main Results:
- Observation of field-induced BKT correlations in weakly coupled spin-1/2 Heisenberg layers.
- Significant BKT regime induced by laboratory magnetic fields tuning XY anisotropy.
- Excellent agreement between experimental and simulated critical temperatures.
Conclusions:
- The magnetic phase diagram is governed by field-tuned XY anisotropy and BKT physics.
- Interlayer exchange coupling plays a role in the transition to 3D correlations.
- NMR and quantum Monte Carlo simulations provide strong evidence for the proposed mechanism.
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