Are the bulk quantum oscillations in SmB6 intrinsic?
In plain words
Some SmB6 crystals show magnetization oscillations typical of metal electrons although their resistance says the bulk is insulating. Other groups attribute the oscillations to surface states or to aluminum inclusions left from crystal growth.
Precise statement
In the Kondo insulator SmB6, de Haas-van Alphen oscillations were reported as two-dimensional surface signals (Li et al. 2014) and as three-dimensional bulk signals with large Fermi surfaces and anomalous low-temperature amplitude growth (Tan et al. 2015, floating-zone crystals); in flux-grown crystals oscillations were traced to embedded Al (2018-2019). Determine whether bulk oscillations exist in stoichiometric, inclusion-free SmB6.
What would settle it
De Haas-van Alphen and specific-heat oscillation measurements on crystals from several growth methods with inclusion content and Sm vacancy density quantified.
Status in the literature
Specific-heat oscillations at the torque frequencies (LaBarre et al., Journal of Physics: Condensed Matter 34, 36LT01, 2022) support a bulk thermodynamic origin in some crystals; dependence on growth method persists.
Related problems
- Special case of Do Kondo insulators host charge-neutral fermions with a Fermi surface · SmB6 bulk oscillations are the SmB6 instance of the Kondo-insulator neutral-fermion question