Hall Coefficient and electron-electron interaction of 2D electrons in Si-MOSFET's

Recent experiments in silicon MOSFETs indicate that the Hall coefficient is independent of magnetic field applied at a small angle with respect to the plane. Below a scattering between spin-up and spin-down carriers is considered to be the main reason for the experimental observation. Comparison of two band model with experiment provides an upper limit for the electron-electron scattering time $\tau_{ee}$ in the dilute 2D electron system as a function of electron density $n_s$. The time $\tau_{ee}$ increases gradually with $n_s$, becoming much greater than the transport scattering time $\tau_p$ for densities $n_s>4 \times 10 ^{11}$ cm$^{-2}$. Strong electron-electron scattering is found for $1.22 \times 10 ^{11} <n_s<3 \times 10 ^{11}$ cm$^{-2}$, the region which is near to the apparent metal insulator transition.