Magnetic-field-induced quantum Hall effect – Hall insulator transition and hopping conductivity in InAs/GaAs quantum dot layers

Abstract

We have investigated the resistance in the temperature range T=0.4– 300 K and magnetotransport in magnetic fields up to 35 T in InAs/GaAs quantum dot layers. In samples with a relatively high carrier concentration the quantum Hall effect-to-Hall insulator transition was observed in high magnetic fields. Two-dimensional Mott variable range hopping conductivity has been observed at low temperatures in samples with low carrier concentration. The localization length correlates very well with the quantum dot cluster size obtained by atomic force microscope.