Spin relaxation in cubic III-V semiconductor low-dimensional structures via the interaction with polar-optical phonons

Spin-relaxation rates have been calculated for the D’yakonov-Perel (DP) mechanism involving the interaction with polar-optical phonons. The inelastic nature of the collisions has been fully taken into account and expressions for the energy-dependent time constants have been found for arbitrary degeneracy and for both strong and weak spin-population differences. We investigate the energy and temperature dependence of the spin-relaxation rates for a range of quantum well (QW) widths and quantum wire (QWR) cross sections. The spin-relaxation time is found to exhibit a monotonic temperature dependence and an $E^{-2}$ dependence on subband energy.

Figure 1

Spin relaxation in a 5 nm GaAs quantum well (QW) at 300 K via the DP mechanism. (a) Effective scattering time associated with the POP interaction. Solid curve ${\tau }_{\mathit{1}}$, dash curve ${\tau }_3$. (b) Spin-relaxation time.

Figure 2

Spin relaxation in a 5 nm GaAs quantum well (QW) at 200 K via the DP mechanism. (a) Effective scattering time associated with the POP interaction. Solid curve ${\tau }_{\mathit{1}}$, dash curve ${\tau }_3$. (b) Spin-relaxation time.

Figure 3

Temperature dependence in GaAs of the 2D DP spin-relaxation time.

Figure 4

Subband energy dependence in GaAs QW of the DP spin-relaxation time.

Figure 5

(a) Variation of effective scattering time with longitudinal energy at 300 K for a quantum wire (QWR) of cross section 4 by 4.1 nm. (b) Variation of spin-relaxation time with longitudinal energy at 300 K for a quantum wire (QWR) of cross section 4 by 4.1 nm.

Figure 6

(a) Variation of effective scattering time with longitudinal energy at 300 K for a quantum wire (QWR) of cross section 4 by 4.5 nm. (b) Variation of spin relaxation time with longitudinal energy at 300 K for a quantum wire (QWR) of cross section 4 by 4.5 nm.

Figure 7

Variation of spin-relaxation time with QWR cross section at 300 K, $\mathrm{Lx}=4\mathrm{nm}$. (a) Ly vs $T_s$. (b) Difference in subband energies vs $T_s$.

Figure 8

Temperature dependence of the spin-relaxation time in a QWR of cross section 4 by 4.1 nm.

Figure 9

Energy dependence of the dimensionless quantity $\Omega \tau$ for temperatures of 200 solid curve and 300 K dashed curve (a) quantum well (b) quantum wire.