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Magnon interactions in a moderately correlated Mott insulator
Qisi Wang1,2, S Mustafi3, E Fogh4
1Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, China. qwang@cuhk.edu.hk.
Nature Communications
|June 24, 2024
Summary
This study quantifies quantum fluctuations in cuprates using resonant inelastic x-ray scattering. SrCuO2 exhibits stronger quantum fluctuations than La2CuO4, indicating proximity to a magnetic quantum critical point and potential for novel magnetic states.
Area of Science:
- Condensed matter physics
- Materials science
- Quantum magnetism
Background:
- Quantum fluctuations significantly impact low-dimensional systems and quantum phase transitions.
- Experimentally measuring quantum fluctuation strength remains challenging.
Purpose of the Study:
- To experimentally probe and quantify quantum fluctuations in Mott insulating cuprates.
- To investigate magnon excitations in SrCuO2 and La2CuO4 thin films.
Main Methods:
- Resonant inelastic x-ray scattering (RIXS) was employed to study magnon excitations.
- An effective Heisenberg Hamiltonian derived from the Hubbard model was used for theoretical analysis.
- Monte Carlo calculations explored competing magnetic orders.
Main Results:
- Single- and bi-magnon dispersions were derived for SrCuO2.
- Magnon-magnon interactions were found crucial for accurately describing single-magnon dispersion in SrCuO2.
- Quantum fluctuations are significantly stronger in SrCuO2 compared to La2CuO4.
Conclusions:
- SrCuO2 is closer to a magnetic quantum critical point than La2CuO4.
- Competing magnetic orders may challenge the antiferromagnetic Néel state in SrCuO2.
- SrCuO2 serves as a unique platform for exploring novel magnetic ground states due to strong quantum fluctuations.
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