  The generalized tight-binding model is developed to investigate the rich and
unique electronic properties of AB-bt (bottom-top) bilayer silicene under
uniform perpendicular electric and magnetic fields. The first pair of
conduction and valence bands, with an observable energy gap, displays unusual
energy dispersions. Each group of conduction/valence Landau levels (LLs) is
further classified into four subgroups, that is, there exist the sublattice-
and spin-dominated LL subgroups. The magnetic-field-dependent LL energy spectra
exhibit irregular behavior corresponding to the critical points of the band
structure. Moreover, the electric field can induce many LL anti-crossings. The
main features of the LLs are uncovered with many van Hove singularities in the
density-of-states and non-uniform delta-function-like peaks in the
magneto-absorption spectra. The feature-rich magnetic quantization directly
reflects the geometric symmetries, intra-layer and inter-layer atomic
interactions, spin-orbital couplings, and the field effects. The results of
this work can be applied to novel designs of $Si$-based nano-electronics and
nano-devices with enhanced mobilities.

Materials Science;Mesoscale and Nanoscale Physics