Long electron dephasing length and disorder-induced spin-orbit coupling in indium tin oxide nanowires

TL;DR

This study investigates quantum-interference effects in indium tin oxide nanowires, revealing long electron dephasing lengths and disorder-induced spin-orbit coupling, with implications for nanoscale quantum devices.

Contribution

It provides the first detailed measurement of electron dephasing and spin-orbit effects in ITO nanowires, highlighting the impact of disorder and dimensional crossover on quantum interference.

Findings

Long dephasing lengths up to 520 nm at 0.25 K

Disorder-induced spin-orbit coupling causes weak-antilocalization below 4 K

Dimensional crossover from 1D to 3D occurs around 12 K

Abstract

We have measured the quantum-interference magnetoresistances in two single indium tin oxide (ITO) nanowires between 0.25 and 40 K, by using the four-probe configuration method. The magnetoresistances are compared with the one-dimensional weak-(anti)localization theory to extract the electron dephasing length $L_\phi$. We found, in a 60-nm diameter nanowire with a low resistivity of $\rho$(10 K) = 185 $\mu \Omega$ cm, that $L_\phi$ is long, increasing from 150 nm at 40 K to 520 nm at 0.25 K. Therefore, the nanowire reveals strict one-dimensional weak-localization effect up to several tens of degrees of Kelvin. In a second 72-nm diameter nanowire with a high resistivity of $\rho$(10 K) = 1030 $\mu \Omega$ cm, the dephasing length is suppressed to $L_\phi$(0.26 K) = 200 nm, and thus a crossover of the effective device dimensionality from one to three occurs at about 12 K. In particular, disorder-induced spin-orbit coupling is evident in the latter sample, manifesting weak-antilocalization effect at temperatures below $\sim$ 4 K. These observations demonstrate that versatile quantum-interference effects can be realized in ITO nanowires by controlling differing levels of atomic defects and impurities.