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Hall effect of triplons in a dimerized quantum magnet
Judit Romhányi1, Karlo Penc2, R Ganesh1
1Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, D-01171 Dresden, Germany.
Nature Communications
|April 14, 2015
Summary
Quantum magnets like SrCu2(BO3)2 exhibit topological properties. Dzyaloshinskii-Moriya interactions create spin-1 Dirac cones, leading to a magnetic quantum Hall effect with protected edge modes.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
Background:
- SrCu2(BO3)2 is a key quantum magnet realizing the Shastry-Sutherland model.
- It features a gapped dimer-singlet ground state and triplon excitations.
- Dzyaloshinskii-Moriya interactions introduce small anisotropies.
Purpose of the Study:
- Investigate the topological nature of triplon band structure in SrCu2(BO3)2.
- Explore the influence of Dzyaloshinskii-Moriya interactions on topological properties.
- Connect these findings to magnetic analogues of quantum Hall effects.
Main Methods:
- Theoretical analysis of triplon band structure.
- Investigating the impact of magnetic fields and anisotropies.
- Predicting observable phenomena like the thermal Hall effect.
Main Results:
- Dzyaloshinskii-Moriya interactions induce topological character in triplon bands.
- A novel spin-1 Dirac cone with three touching bands is identified.
- Applied magnetic fields create topological bands with Chern numbers ±2, analogous to the integer quantum Hall effect.
- Topologically protected edge modes are predicted.
Conclusions:
- SrCu2(BO3)2 serves as a magnetic analogue of the integer quantum Hall effect.
- The material supports topologically protected edge modes.
- A strong thermal Hall signature is predicted in the topological regime.
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