Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires

TLDR

Dirac electronic materials beyond graphene and topological insulators have attracted considerable attention, and Cd₃As₂ is a Dirac semimetal with linear dispersion in all three momentum directions that can be viewed as a three‑dimensional analogue of graphene. The study aims to provide experimental evidence of the chiral anomaly in Cd₃As₂ by probing its magnetotransport properties. Negative magnetoresistance in individual Cd₃As₂ nanowires is modulated by gate voltage and temperature through tuning the density of chiral states at the Fermi level and the inter‑valley scattering between Weyl nodes. Large negative magnetoresistance of up to 63 % at 60 K and 11 % at 300 K in individual Cd₃As₂ nanowires provides evidence for the chiral anomaly and enhances understanding of Weyl fermions in Dirac semimetals.

Abstract

Dirac electronic materials beyond graphene and topological insulators have recently attracted considerable attention. Cd3As2 is a Dirac semimetal with linear dispersion along all three momentum directions and can be viewed as a three-dimensional analogue of graphene. By breaking of either time-reversal symmetry or spatial inversion symmetry, the Dirac semimetal is believed to transform into a Weyl semimetal with an exotic chiral anomaly effect, however the experimental evidence of the chiral anomaly is still missing in Cd3As2. Here we show a large negative magnetoresistance with magnitude of -63% at 60 K and -11% at 300 K in individual Cd3As2 nanowires. The negative magnetoresistance can be modulated by gate voltage and temperature through tuning the density of chiral states at the Fermi level and the inter-valley scatterings between Weyl nodes. The results give evidence of the chiral anomaly effect and are valuable for understanding the Weyl fermions in Dirac semimetals.