Nuclear quadrupolar spin-lattice relaxation in some III-V compounds

Abstract

Measurements of the spin-lattice relaxation rates in the group-III-V compounds, GaAs, GaSb, InAs, and InSb, are presented as a function of temperature from 4 to 300 K. These rates, except for GaSb, are separated into magnetic and quadrupolar parts. The quadrupolar rates are separated into relaxation by acoustic phonons and that by optical phonons. A simple phenomenological model fits the data to within 5% over the temperature range. The optical phonons couple more strongly to the III nuclei than to the V. This differential coupling is discussed in terms of a dipole mechanism for the electric field gradients.