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

TL;DR

This study demonstrates quantum interference effects in bismuth nanowires through Aharonov-Bohm oscillations, revealing surface state contributions and subband structures in magnetoresistance at low temperatures.

Contribution

It provides experimental evidence of surface state quantum interference in bismuth nanowires and models the subband structure due to surface states.

Findings

Observation of h/2e and h/e oscillations in magnetoresistance.

Surface states form a high-conductance tube around nanowires.

Fermi energy of surface band estimated at 15 meV.

Abstract

We report the observation of a 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-nm wires were investigated in magnetic fields of up to 14 T. For 55 nm nanowires, longitudinal magnetoresistance periods of 0.8 and 1.6 T that were observed at magnetic fields over 4 T are assigned to h/2e to h/e magnetic flux modulation. The same modes of oscillation were observed in 75-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-nm nanowires, the Fermi energy of the surface band is estimated to be 15 meV. An interpretation of the magnetoresistance oscillations in terms of a subband structure in the surface states band due to quantum interference in the tube is presented.