title: Negative magnetoresistance in Dirac semimetal Cd3As2.
abstract: A large negative magnetoresistance (NMR) is anticipated in topological semimetals in parallel magnetic fields, demonstrating the chiral anomaly, a long-sought high-energy-physics effect, in solid-state systems. Recent experiments reveal that the Dirac semimetal Cd3As2 has the record-high mobility and positive linear magnetoresistance in perpendicular magnetic fields. However, the NMR has not yet been unveiled. Here we report the observation of NMR in Cd3As2 microribbons in parallel magnetic fields up to 66% at 50 K and visible at room temperatures. The NMR is sensitive to the angle between magnetic and electrical fields, robust against temperature and dependent on the carrier density. The large NMR results from low carrier densities in our Cd3As2 samples, ranging from 3.0 × 10(17) cm(-3) at 300 K to 2.2 × 10(16) cm(-3) below 50 K. We therefore attribute the observed NMR to the chiral anomaly. In perpendicular magnetic fields, a positive linear magnetoresistance up to 1,670% at 14 T and 2 K is also observed.
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: He
authors.affiliation: Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055, China.
authors.forename: Hai-Zhou
authors.initials: HZ
authors.lastname: Lu
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Huachen
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Hongchao
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Ma
authors.affiliation: Department of Electronics and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Fan
authors.affiliation: Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Shun-Qing
authors.initials: SQ
authors.lastname: Shen
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Jiannong
authors.initials: J
authors.lastname: Wang