Observation of a two-dimensional Fermi surface and Dirac dispersion in YbMnSb2

Author(s): Kealhofer, R; Jang, S; Griffin, SM; John, C; Benavides, KA; Doyle, S; Helm, T; Moll, PJW; Neaton, JB; Chan, JY; Denlinger, JD; Analytis, JG | Abstract: © 2018 American Physical Society. We present the crystal structure, electronic structure, and transport properties of the material YbMnSb2, a candidate system for the investigation of Dirac physics in the presence of magnetic order. Our measurements reveal that this system is a low-carrier-density semimetal with a two-dimensional Fermi surface arising from a Dirac dispersion, consistent with the predictions of density-functional-theory calculations of the antiferromagnetic system. The low temperature resistivity is very large, suggesting that scattering in this system is highly efficient at dissipating momentum despite its Dirac-like nature.