Gate-tuned Aharonov-Bohm interference of surface states in a quasiballistic Dirac semimetal nanowire*

We report an observation of a topologically protected transport of surface carriers in a quasiballistic Cd₃As₂
nanowire. The nanowire is thin enough for the spin-textured surface carriers to form 1D subbands, demonstrating
conductance oscillations with gate voltage even without magnetic field. The π-phase shift of Aharonov-Bohm
oscillations can periodically appear/disappear by tuning gate voltage continuously. Such a π-phase shift stems
from the magnetic field induced helical modes in the surface subbands.