Origin of conductance oscillations in the InAs/GaSb hybridization gap
In plain words
Quantum wells of InAs and GaSb form an insulator whose small energy gap comes from mixing of electron and hole bands, yet their conductance oscillates in a magnetic field when the electron density is tuned into the gap. Whether this is the band-mixing mechanism proposed for SmB6 or something else is unknown.
Precise statement
In InAs/GaSb quantum spin Hall wells gated into the hybridization gap, the conductance oscillates periodically in 1/B with an unusual temperature dependence of the amplitude (Han, Li, Zhang, Sullivan and Du, Physical Review Letters 123, 126803, 2019). Determine whether the frequency, the temperature dependence of the amplitude and the gate dependence match Landau quantization of the inverted hybridized bands (Knolle and Cooper 2015) or require another source (residual bulk carriers, edge conduction, excitonic correlations).
What would settle it
Simultaneous transport and capacitance oscillation measurements versus gate voltage, temperature and in-plane field inside the gap, compared with the oscillation spectrum computed from the measured band structure.
Status in the literature
Unverified note
Theory continues to examine band-structure effects such as spin-orbit coupling on these oscillations (Du et al., Physical Review B, 2026); no account is agreed.