Efros–Shklovskii hopping in the electronic transport in 2D p-GaAs

Abstract

We have investigated the resistivity of a 2D hole system in GaAs in the temperature range 200 mK < T < 800 mK at zero magnetic field and low hole densities when the system is near the metal–insulator transition in the insulating side. We have found that the resistivity follows the Efros–Shklovskii variable range hopping (ES-VRH) law, this behaviour is consistent with the existence of a Coulomb gap. The resistivity scales with temperature and the prefactor has been found independent of temperature and density, thus confirming the dominance of hole–hole interaction.