Ultrahigh mobility and giant magnetoresistance in the Dirac semimetal Cd3As2

• Published in: Nature materials Vol. 14; no. 3; pp. 280 - 284
• Main Authors: Liang, Tian, Gibson, Quinn, Ali, Mazhar N., Liu, Minhao, Cava, R. J., Ong, N. P.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2015; Nature Publishing Group
• Subjects: 639/766/119/2792; Biomaterials; Condensed Matter Physics; Crystals; letter; Magnetic fields; Magnetism; Materials Science; Mobility; Nanotechnology; Optical and Electronic Materials; Studies
• ISSN: 1476-1122; 1476-4660; 1476-4660
• DOI: 10.1038/nmat4143

Three-dimensional analogues of graphene have recently been synthesized. The transport properties of such a Dirac semimetal, Cd 3 As 2 , have been studied, revealing an unexpected mechanism that suppresses backscattering dramatically. Dirac and Weyl semimetals are 3D analogues of graphene in which crystalline symmetry protects the nodes against gap formation 1 , 2 , 3 . Na 3 Bi and Cd 3 As 2 were predicted to be Dirac semimetals 4 , 5 , and recently confirmed to be so by photoemission experiments 6 , 7 , 8 . Several novel transport properties in a magnetic field have been proposed for Dirac semimetals 2 , 9 , 10 , 11 . Here, we report a property of Cd 3 As 2 that was unpredicted, namely a remarkable protection mechanism that strongly suppresses backscattering in zero magnetic field. In single crystals, the protection results in ultrahigh mobility, 9 × 10 6 cm 2 V −1 s −1 at 5 K. Suppression of backscattering results in a transport lifetime 10 4 times longer than the quantum lifetime. The lifting of this protection by the applied magnetic field leads to a very large magnetoresistance. We discuss how this may relate to changes to the Fermi surface induced by the applied magnetic field.