  A Dirac-type energy spectrum was demonstrated in gapless ultra-short-period
metamorphic InAsSb/InSb superlattices by angle-resolved photoemission
spectroscopy (ARPES_ measurements. The Fermi velocity value 7.4x10^5 m/s in a
gapless superlattice with a period of 6.2nm is in a good agreement with the
results of magneto-absorption experiments. An "inverted" bandgap opens in the
center of the Brillouin zone at higher temperatures and in the SL with a larger
period. The ARPES data indicate the presence of a surface electron accumulation
layer
