Hall coefficient and electron-electron interaction of two-dimensional electrons in Si MOSFETs

Recent experiments in silicon metal-oxide-semiconductor field-effect transistors 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 the two-band model with experiment provides an upper limit for the electron-electron scattering time τₑₑ in the dilute two-dimensional electron system as a function of electron density nₛ. The time τₑₑ increases gradually with nₛ, becoming much greater than the transport scattering time τₚ for densities nₛ>4×10¹¹ cm^-2. Strong electron-electron scattering is found for 1.22×10¹¹<nₛ<3×10¹¹ cm^-2, the region which is near to the apparent metal-insulator transition.