Insulating and fractional quantum hall states in the first excited Landau level

Phys Rev Lett. 2002 Feb 18;88(7):076801. doi: 10.1103/PhysRevLett.88.076801. Epub 2002 Jan 30.

Abstract

The observation of new insulating phases of two-dimensional electrons in the first excited Landau level is reported. These states, which are manifested as reentrant integer quantized Hall effects, exist alongside well-developed even-denominator fractional quantized Hall states at nu = 7/2 and 5/2 and new odd-denominator states at nu = 3+1/5 and 3+4/5.