Localisation and the metal-insulator transition in two dimensions

We investigate the insulating and metallic behaviour found in strongly inte racting, dilute 2D GaAs hole systems. At the lowest carrier densities insul ating behaviour is observed with the resistivity increasing with decreasing temperature. As the carrier density is increased a transition to metallic behaviour occurs. Despite exhibiting all the properties of the metallic beh aviour observed in other material systems, localising corrections due both to weak localisation and hole-hole interactions are still present in the "m etallic" regime. These results suggest that the metallic behaviour may only be a finite temperature effect, and we investigate various semi-classical mechanisms that might be responsible for this metallic-like behaviour. (C) 2001 Published by Elsevier Science B.V.