A low-temperature insulating phase at for 2D holes in high-mobility heterostructures with Landau level degeneracy

Abstract

Magneto-transport measurements of the 2D hole system (2DHS) in p-type Si - heterostructures identify the integer quantum Hall effect (IQHE) at dominantly odd-integer filling factors and two low-temperature insulating phases (IPs) at and , with re-entrance to the quantum Hall effect at . The temperature dependence, current - voltage characteristics, and tilted field and illumination responses of the IP at indicate that the important physics is associated with an energy degeneracy of adjacent Landau levels of opposite spin, which provides a basis for consideration of an intrinsic, many-body origin.