 Incompressible quantum Hall edge strip

An incompressible quantum Hall edge strip is an edge region where the local chemical potential lies in a gap between available electron states. Small potential changes then alter the local electron density only weakly, so that region cannot screen an external field as effectively as a neighboring compressible quantum Hall edge strip.

In the self-consistent electrostatic picture, incompressible regions alternate with compressible ones as the confining potential varies toward an edge. Much of the potential change can occur across the incompressible regions. Their widths depend on the gap and density profile; a prescribed unscreened edge potential misses the redistribution that produces the strips.^[ref]