  We performed an angle-resolved photoemission spectroscopy study of BaFe2As2,
which is the parent compound of the so-called 122 phase of the iron-pnictide
high-temperature superconductors. We reveal the existence of a Dirac cone in
the electronic structure of this material below the spin-density-wave
temperature, which is responsible for small spots of high photoemission
intensity at the Fermi level. Our analysis suggests that the cone is slightly
anisotropic and its apex is located very near the Fermi level, leading to tiny
Fermi surface pockets. Moreover, the bands forming the cone show an anisotropic
leading edge gap away from the cone that suggests a nodal spin-density-wave
description.
