We study Aharonov-Bohm (AB) conductance oscillations arising from the surface states of a topological insulator nanowire, when a magnetic field is applied along its length. With strong surface disorder, these oscillations are predicted to have a component with anomalous period ${\Phi }_0=hc/e$, twice the conventional period. The conductance maxima are achieved at odd multiples of $\frac{1}{2}{\Phi }_0$, implying that a $\pi$ AB phase for electrons strengthens the metallic nature of surface states. This effect is special to topological insulators, and serves as a defining transport property. A key ingredient, the surface curvature induced Berry phase, is emphasized here. We discuss similarities and differences from recent experiments on ${\mathrm{Bi}}_2{\mathrm{Se}}_3$ nanoribbons, and optimal conditions for observing this effect.

• Received 20 May 2010

DOI:https://doi.org/10.1103/PhysRevLett.105.206601