Itinerant antiferromagnetism in BaCr2 As2: Experimental characterization and electronic structure calculations

We report single-crystal synthesis, specific-heat and resistivity measurements and electronic structure calculations for BaCr2 As2. This material is a metal with itinerant antiferromagnetism, similar to the parent phases of Fe-based high-temperature superconductors, but differs in magnetic order. Comparison of bare band-structure density of states and the low-temperature specific heat implies a mass renormalization of ∼2. BaCr2 As2 shows stronger transition-metal-pnictogen covalency than the Fe compounds, and in this respect is more similar to BaMn2 As2. This provides an explanation for the observation that Ni and Co doping is effective in the Fe-based superconductors, but Cr or Mn doping is not.