Dipole trap model for the metal-insulator transition in gated silicon-inversion layers

Abstract

In order to investigate the metal-insulator transition in high-mobility Si-metal-oxide-semiconductor structures, we have precised and further developed the dipole trap model as originally proposed by Altshuler and Maslov [Phys. Rev. Lett. 82, 145 (1999)]. Our additional numerical treatment enables us to drop several approximations and to introduce a limited spatial depth of the trap states inside the oxide as well as to include a distribution of trap energies. Depending on the type and width of distribution, the metallic state appears more or less pronounced as observed in experiments on samples with different quality.