Peculiarities of the microwave magnetoresistance of compensated Ge : As near the metal-insulator transition

The contactless technique of electron paramagnetic resonance was used to me asure magnetoresistance (MR) phenomena in heavily doped and compensated Ge: As both in the metallic and insulator phases near the metal-insulator trans ition. The field and temperature characteristics of the MR derivative show two main origins: weak localization in the low fields resulting in negative MR and electron interaction in strong fields resulting in positive MR. For insulating samples only a small negative MR is observed with a low-field c haracteristic behavior. The results obtained are compared with the quantum corrections theory.