  It was experimentally demonstrated that short-period metamorphic
InAs1-xSbx/InAs1-ySby superlattices with ultra low bandgap have properties of a
Dirac material. Cyclotron resonance and interband magneto-absorption peaks in
superlattices with ultra-low bandgaps demonstrate a square root dependence on
the magnetic field for a range up to 16 T (energy range up to 300meV). This
directly indicates the linearity of the electron dispersion. The Fermi velocity
can be controlled by varying the overlap between electron and hole states in
the superlattice. The dependence of the cyclotron resonance energy on the
magnetic field parallel to the superlattice plane demonstrates that the
electron dispersion in the growth direction can be characterized by an
effective mass of 0.028m0 in a superlattice with a period of 6 nm and 0.045m0
in a superlattice with a period of 7.5 nm. Extreme design flexibility makes the
short-period metamorphic InAs1-xSbx/InAs1-ySby superlattice a new prospective
platform for studying the effects of charge carrier chirality and topologically
nontrivial states in structures with the inverted bandgaps.
