Density inhomogeneity driven metal–insulator transition in 2D p-GaAs

• Electrical conductivity σ(T) and σ(ps) in 2D p-GaAs is studied.
• Percolation-induced metal–insulator transition is observed.
• Critical density is lower than that indicated by the slope dσ/dT.

In this work, we present a study of the temperature and carriers density dependence of the electrical transport of high mobility two dimensional hole system grown on the (311) surface of GaAs. At low temperatures, the analysis of the variation of conductivity data as σ(ps)∝(ps−psc⁎)δ shows that a density inhomogeneity in the metallic phase leading to percolation-type transition to an insulating state at a critical density psc⁎ that decrease slowly with increasing temperature and found to be lower than the corresponding estimate psc based on the sign of the slope dρ/dT. The experimental values of the exponent δexp are close to theoretical values corresponding to the 2D percolation transition (δth=4/3).