Dirac energy spectrum and inverted bandgap in metamorphic InAsSb/InSb superlattices

Abstract

A Dirac-type energy spectrum was demonstrated in gapless ultrashort-period metamorphic InAsSb/InSb superlattices by angle-resolved photoemission spectroscopy (ARPES) measurements. The Fermi velocity value of 7.4 × 105 m/s in a gapless superlattice with a period of 6.2 nm is in good agreement with the results of magnetoabsorption experiments. An "inverted" bandgap opens in the center of the Brillouin zone at higher temperatures and in the superlattice with a larger period. The ARPES data indicate the presence of a surface electron accumulation layer.