Electron spin relaxation via flexural phonon modes in semiconducting carbon nanotubes

TL;DR

This paper investigates how flexural phonon modes in semiconducting carbon nanotubes induce electron spin relaxation, revealing temperature, magnetic field, and diameter dependencies, with relaxation times around 30 microseconds at room temperature.

Contribution

It introduces a theoretical model for spin relaxation via flexural phonons in carbon nanotubes, highlighting a mechanism distinct from hyperfine interactions.

Findings

Relaxation rate depends on temperature, magnetic field, and nanotube diameter.

Spin relaxation time can be as short as 30 microseconds at room temperature.

Flexural phonons significantly contribute to spin relaxation at high temperatures.

Abstract

This work considers the g-tensor anisotropy induced by the flexural thermal vibrations in one-dimensional structures and its role in electron spin relaxation. In particular, the mechanism of spin-lattice relaxation via flexural modes is studied theoretically for localized and delocalized electronic states in semiconducting carbon nanotubes in the presence of magnetic field. The calculation of one-phonon spin-flip process predicts distinctive dependencies of the relaxation rate on temperature, magnetic field and nanotube diameter. Comparison with the spin relaxation caused by the hyperfine interaction clearly suggests the relative efficiency of the proposed mechanism at sufficiently high temperatures. Specifically, the longitudinal spin relaxation time in the semiconducting carbon nanotubes is estimated to be as short as 30 microseconds at room temperature.