arXiv subjects

P. D. Rose

Publications and source records attributed to P. D. Rose.

3 recordsLinked to original sources

arXiv1999

Weak localisation, hole-hole interactions and the "metal"-insulator transition in two dimensions

A detailed investigation of the metallic behaviour in high quality GaAs-AlGaAs two dimensional hole systems reveals the presence of quantum corrections to the resistivity at low temperatures. Despite the low density ($r_{s}>10$) and high quality of these systems, both weak localisation (observed via negative magnetoresistance) and weak hole-hole interactions (giving a correction to the Hall constant) are present in the so-called metallic phase where the resistivity decreases with decreasing temperature. The results suggest that even at high $r_{s}$ there is no metallic phase at T=0 in two dimensions.

cond-mat.mes-hall↗

arXiv1998

Re-entrant insulator-metal-insulator transition at B=0 in a two dimensional hole gas

We report the observation of a re-entrant insulator--metal--insulator transition at B=0 in a two dimensional (2D) hole gas in GaAs at temperatures down to 30mK. At the lowest carrier densities the holes are strongly localised. As the carrier density is increased a metallic phase forms, with a clear transition at σ= ~5e^2/h. Further increasing the density weakens the metallic behaviour, and eventually leads to the formation of a second insulating state for σ> ~50e^2/h. In the limit of high carrier densities, where k_F.l is large and r_s is small, we thus recover the results of previous work on weakly interacting systems showing the absence of a metallic state in 2D.

cond-mat.str-el↗

arXiv1997

Metal-insulator transition at B=0 in a dilute two dimensional GaAs-AlGaAs hole gas

We report the observation of a metal insulator transition at B=0 in a high mobility two dimensional hole gas in a GaAs-AlGaAs heterostructure. A clear critical point separates the insulating phase from the metallic phase, demonstrating the existence of a well defined minimum metallic conductivity sigma(min)=2e/h. The sigma(T) data either side of the transition can be `scaled' on to one curve with a single parameter (To). The application of a parallel magnetic field increases sigma(min) and broadens the transition. We argue that strong electron-electron interactions (rs = 10) destroy phase coherence, removing quantum intereference corrections to the conductivity.

cond-mat.str-el↗