Freezing out of a low-energy bulk spin exciton in SmB6
Abstract
The Kondo insulator SmB6 is purported to develop into a robust topological insulator at low temperatures. Yet there are several puzzling and unexplained physical properties of the insulating bulk. It has been proposed that bulk spin excitons may be the source of these anomalies and may also adversely affect the topologically protected metallic surface states. Here, we report muon spin rotation measurements of SmB6 that show thermally activated behavior for the temperature dependence of the transverse-field relaxation rate below 20 K and a decreasing contact hyperfine field contribution to the positive muon Knight shift below 5–6 K. Our data are consistent with the freezing out of a bulk low-energy (~1 meV) spin exciton concurrent with the appearance of metallic surface conductivity. Furthermore, our results support the idea that spin excitons play some role in the anomalous low-temperature bulk properties of SmB6.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 15, 2018
- Source ID
- 10.1038/s41535-018-0110-7
Entities
People
- Alex C. Y. Fang
- Anand Pal
- Jeff E. Sonier
- Johnpierre Paglione
- Kolawole Akintola
- Matt Potma
- Sarah R. Dunsiger
- Shanta Saha
- X. F. Wang
Organizations
- Air Force Office of Scientific Research
- Gordon and Betty Moore Foundation
- Natural Sciences and Engineering Research Council