The Anderson transition in a magnetic field experimental evidence for a new phase diagram

We present results on the low-temperature resistivity of n-type InP, with an impurity concentration n just below the critical concentration, nc, for the metal-insulator transition. A detailed study of the influence of magnetic fields between 0 and 3·5 T gives evidence for an insulator-metal transition followed by the usual metal-insulator transition. These results are in agreement with a new phase diagram incorporating localization by shrinkage of orbits at high magnetic fields and delocalization due to interference effects at low magnetic fields.