• A
  • A
  • A
  • ABC
  • ABC
  • ABC
  • А
  • А
  • А
  • А
  • А
Regular version of the site

Article

Magnetic resonance probing of ground state in the mixed valence correlated topological insulator SmB6

Scientific Reports. 2018. Vol. 8. P. 1-8.
Demishev S. V., Gilmanov M., Samarin A., Semeno A., Sluchanko N., Samarin N., Bogach A., Shitsevalova N., Filipov V., Karasev M., Glushkov V. V.

Introducing of topological insulator concept for fluctuating valence compound – samarium hexaboride
– has recently initiated a new round of studies aimed to clarify the nature of the ground state in this
extraordinary system with strong electron correlations. Here we discuss the data of magnetic resonance
in the pristine single crystals of SmB6 measured in 60 GHz cavity experiments at temperatures
1.8–300 K. The microwave study as well as the DC resistivity and Hall effect measurements
performed for the different states of SmB6 [110] surface prove definitely the existence of the layer
with metallic conductivity increasing under lowering temperature below 5 K. Four lines with the
g-factors g ≈ 2 are found to contribute to the ESR-like absorption spectrum that may be attributed to
intrinsic paramagnetic centers on the sample’s surface, which are robust with respect to the surface
treatment. The temperature dependence of integrated intensity I(T) for main paramagnetic signal
is found to demonstrate anomalous critical behavior I(T) ~ (T* − T)ν with characteristic temperature
T* = 5.34 ± 0.05 K and exponent ν = 0.38 ± 0.03 indicating possible magnetic transition at the SmB6
[110] surface. Additional resonant magnetoabsorption line, which may be associated with either donorlike
defects or cyclotron resonance mode corresponding to the mass mc ~ 1.2m0, is reported.