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Quantum-critical spin dynamics in quasi-one-dimensional antiferromagnets
S Mukhopadhyay1, M Klanjšek, M S Grbić
1Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), UJF, UPS and INSA, BP 166, 38042 Grenoble Cedex 9, France.
Physical Review Letters
|December 11, 2012
Summary
Quantum criticality in antiferromagnets was studied using nuclear spin-lattice relaxation rate. Spin excitations evolve from magnons to spinons, showing universal behavior across different quantum systems.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
Background:
- Quasi-one-dimensional quantum antiferromagnets exhibit complex spin dynamics.
- Understanding spin excitation evolution is crucial for quantum criticality studies.
Purpose of the Study:
- To investigate spin dynamics in gapped quantum antiferromagnets under varying magnetic fields.
- To explore the transition from gapped to gapless states and its relation to quantum criticality.
Main Methods:
- Utilized nuclear spin-lattice relaxation rate (T(1)(-1)) measurements.
- Analyzed spin dynamics as a function of applied magnetic field in two distinct quantum systems.
Main Results:
- Confirmed spin excitations transition from magnons to spinons.
- Observed a continuous variation in T(1)(-1) that scales with quantum criticality.
- Extracted a critical exponent for T(1)(-1) consistent across both systems.
Conclusions:
- Demonstrated universal quantum-critical behavior in quasi-one-dimensional quantum antiferromagnets.
- The observed scaling of T(1)(-1) provides evidence for universality in quantum criticality.
- Spin excitation evolution is a key indicator of quantum phase transitions.
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