2014/04/30 by Tian Liang, Quinn Gibson, Mazhar N. Ali +3 · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1038/nmat4143
published as Nat. Mat. 14, 280 (2015) · Main text has 7 pages, 4 figures and 1 table. Text has been re-written with new results added. Supplement has 8 pages, 13 figures and 1 table, Nature Materials online Nov 24, 2014
arxiv created 2014/11/24 · arxiv updated 2017/06/19
Dirac semimetals and Weyl semimetals are 3D analogs of graphene in which crystalline symmetry protects the nodes against gap formation [1-3]. Na3Bi and Cd3As2 were predicted to be Dirac semimetals [4,5], and recently confirmed to be so by photoemission [6-8]. Several novel transport properties in a magnetic field \bf H have been proposed for Dirac semimetals [2,9-11]. Here we report an interesting property in Cd3As2 that was unpredicted, namely a remarkable protection mechanism that strongly suppresses back-scattering in zero \bf H. In single crystals, the protection results in a very high mobility that exceeds >107 cm2/Vs below 4 K. Suppression of backscattering results in a transport lifetime 104× longer than the quantum lifetime. The lifting of this protection by \bf H leads to an unusual giant \bf H-linear magnetoresistance that violates Kohler's rule. We discuss how this may relate to changes to the Fermi surface induced by \bf H.