Spin and phase coherence lengths in InAs wires with diffusive boundary scattering

Measurements of low-temperature magnetotransport in lithographic wires of submicron widths fabricated from high-mobility AlGaSb/InAs/AlGaSb two-dimensional electron system heterostructures are presented. The dependence of the spin and phase coherence lengths on wire width and diffusion constant is investigated by analyzing the conductance in low applied magnetic fields with antilocalization models. Predominantly diffusive boundary scattering is deduced from the magnitude and wire width dependence of the conductance. Diffusive boundary scattering leads to a diffusion constant decreasing with wire width and hence allows the dependence of spin coherence on wire width and diffusion constant to be investigated concurrently. The spin coherence lengths are experimentally found to be proportional to the ratio of the diffusion constant to wire width. The phase coherence lengths follow Nyquist decoherence for low-dimensional wires.