Weak localisation and inter-quantum Hall effect transitions in a 2D Si/SiGe hole system

Weak localisation parameters have been determined for the 2D hole system in a strained Si/Si1-xGex heterostructure. It has been shown that by removing the effect of the lowest Landau level, the v = 2 to v = 1 quantum Hall eff ect transition can be considered to be a quantum Hall effect to Hall insula tor transition, which can be roughly scaled using a temperature scaling exp onent of kappa = 0.70 +/- 0.06. Previously, a similar kappa was determined for the v = 1 to Hall insulator transition in this sample. The experimental value of kappa is consistent with the theoretical value if the value of th e temperature exponent of the phase relaxation time (p = 1.55) extracted fr om the low field weak localisation behaviour is utilised. (C) 2001 Elsevier Science B.V. All rights reserved.