Multiple Phases with the Same Quantized Hall Conductance in a Two-Subband System

Quantized ν = 5/2 state in a two-subband quantum hall system.

The evolution of the fractional quantum Hall state at filling 5/2 is studied in density tunable two-dimensional electron systems formed in wide wells in which it is possible to induce a transition from single- to two-subband occupancy. In 80 and 60 nm wells, the quantum Hall state at 5/2 filling of the lowest subband is observed even when the second subband is occupied. In a 50 nm well, the 5/2...

Universal quantized spin-Hall conductance fluctuation in graphene.

We report theoretical investigations of the quantized spin-Hall conductance fluctuation of graphene in the presence of disorder. Two graphene models that exhibit the quantized spin-Hall effect (QSHE) are analyzed. Model I is with unitary symmetry under an external magnetic field B not = 0 but with a zero spin-orbit interaction, t(SO)=0. Model II is with symplectic symmetry where B=0 but t(SO) n...

The Quantized Hall Effect

The Quantized Hall Effect

This variation on a classical phenomenon makes it possible, even in an irregular sample, to measure fundamental constants with an accuracy rivaling that of the most precise measurements yet made F ew areas of modern science have effect, a planar sample of conductive been studied as intensively as the physics of semiconducting mate-material is placed in a magnetic field and thus obtain quantitie...

Two-subband quantum Hall effect in parabolic quantum wells

The low-temperature magnetoresistance of parabolic quantum wells displays pronounced minima between integer filling factors. Concomitantly the Hall effect exhibits overshoots and plateaulike features next to well-defined ordinary quantum Hall plateaus. These effects set in with the occupation of the second subband. We discuss our observations in the context of single-particle Landau fan charts ...