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Magnetic ground state of FeSe.
Qisi Wang1, Yao Shen1, Bingying Pan1
1State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
Nature Communications
|July 20, 2016
Summary
High-temperature superconductor FeSe exhibits both Néel and stripe spin fluctuations. Its magnetic ground state is a novel quantum-disordered paramagnet, distinct from other iron-based superconductors.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Magnetism
Background:
- Understanding the magnetism in high-temperature superconductors is key to identifying their pairing mechanism.
- Cuprate and iron-pnictide superconductors display Néel and stripe magnetic order, respectively.
- FeSe, the simplest iron-based superconductor, presents nematic order but lacks magnetic order in its parent phase, making its magnetic ground state a subject of debate.
Purpose of the Study:
- To investigate the magnetic properties and ground state of the iron-based superconductor FeSe.
- To clarify the nature of spin fluctuations and their relationship with nematic order in FeSe.
Main Methods:
- Inelastic neutron-scattering experiments were conducted on FeSe at 110 K.
- Analysis of spin fluctuations over a wide energy range.
Main Results:
- Both stripe and Néel spin fluctuations were observed in FeSe at 110 K.
- A significant transfer of spectral weight from Néel to stripe spin fluctuations occurs upon entering the nematic phase.
- The total fluctuating magnetic moment in FeSe is approximately 60% larger than in BaFe2As2.
Conclusions:
- FeSe hosts a novel S=1 nematic quantum-disordered paramagnetic state.
- This state acts as an intermediate between Néel and stripe magnetic instabilities.
- FeSe represents a unique case among iron-based superconductors due to its distinct magnetic behavior.
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