Observation of a Two-Dimensional Fermi Surface and Dirac Dispersion in YbMnSb₂



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.



Antiferromagnetism, Electronic structure, Fermi surfaces, Crystals--Structure


"R.K. is supported by the National Science Foundation (NSF) Graduate Research Fellowship under Grant No. DGE-1106400. S.J., C.J., J.G.A., and much of this work received support from the Gordon and Betty Moore Foundation under Grant No. GBMF4374. R.K., C.J., S.D., and J.G.A. also acknowledge the support from the NSF under Grant No. 1607753. S.J., S.M.G., J.D.D., and J.B.N. were supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the U.S. Department of Energy under Contract No. DE-AC02-05-CH11231. Computational resources provided in part by the Molecular Foundry were supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy, also under Contract No. DE-AC02-05-CH11231. S.M.G. acknowledges financial support by the Swiss National Science Foundation Early Postdoctoral Mobility Program. K.A.B. and J.Y.C. acknowledge partial support from NSF DMR-1360863."


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