We investigated the magnetoresistive behavior of an ideal Dirac semimetal—high-quality single crystals of ${\mathrm{Cd}}_3{\mathrm{As}}_2$ with a Fermi level very close to the Dirac point. A large linear magnetoresistance (LMR), up to 3100% in a magnetic field of 14 T, was observed at a temperature of $T=2\mathrm{K}$. The detailed field and temperature dependencies reveal that the LMR occurs only when the Zeeman energy surpasses the thermal energy. Our result hints that the field-induced relative shifting of the two Weyl-Fermi surfaces in each Dirac cone in momentum space is likely responsible for the LMR behavior.

• Received 26 May 2014
• Revised 30 July 2015

DOI:https://doi.org/10.1103/PhysRevB.92.081306