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Interaction driven subgap spin exciton in the Kondo insulator SmB6
W T Fuhrman1, J Leiner2, P Nikolić3
1Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Physical Review Letters
|February 7, 2015
Summary
Researchers observed a novel resonant mode in the topological Kondo insulator SmB6 using inelastic neutron scattering. This mode provides insights into the material
Area of Science:
- Condensed matter physics
- Materials science
- Quantum materials
Background:
- Topological Kondo insulators like SmB6 exhibit unique electronic properties due to strong electron correlations and spin-orbit coupling.
- Understanding the low-energy excitations in these materials is crucial for exploring their potential applications.
Purpose of the Study:
- To investigate the nature of a specific resonant mode observed in SmB6.
- To correlate this mode with the material's band structure and electronic properties.
Main Methods:
- Inelastic neutron scattering (INS) was employed to probe magnetic excitations.
- A slave-boson treatment of the Anderson Hamiltonian was used to model the electronic structure.
Main Results:
- A 14 meV coherent resonant mode was identified and mapped in SmB6.
- The resonant intensity was localized at specific high-symmetry points (X and R) and showed minimal dispersion.
- The observed mode is consistent with a spin exciton originating from the hybridized band structure.
Conclusions:
- The study reveals a spin exciton below the charge gap in SmB6.
- The findings link inelastic neutron scattering observations to band inversion in topological Kondo insulators.
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