Quantum interference of surface states in bismuth nanowires probed by the Aharonov-Bohm oscillatory behavior of the magnetoresistance

Abstract

We report the observation of an oscillatory dependence of the low-temperature resistance of individual single-crystal bismuth nanowires on the Aharonov-Bohm phase of the magnetic flux threading the wire. 55 and $75\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ wires were investigated in magnetic fields of up to $14\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. For $55\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ nanowires, longitudinal magnetoresistance periods of 0.8 and $1.6\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ that were observed at magnetic fields over $4\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ are assigned to $h∕2e$ to $h∕e$ magnetic flux modulation. The same modes of oscillation were observed in $75\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ wires. The observed effects are consistent with models of the Bi surface where surface states give rise to a significant population of charge carriers of high effective mass that form a highly conducting tube around the nanowire. In the $55\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ wires, the Fermi energy of the surface band is estimated to be $18\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$. An interpretation of the magnetoresistance oscillations in terms of a subband structure in the surface state band caused by quantum interference in the tube is presented.