---
title: "Fractional quantum Hall effect: the plateau required a correlated liquid"
description: "What went beyond the integer Hall picture when the lowest Landau level was only partly filled?"
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[Magnetism, disorder and topological response](https://sandboxphysics.com/stories/condensed-matter/#magnetism)

Materials · Measurements · Explanation

# Fractional quantum Hall effect: the plateau required a correlated liquid

What went beyond the integer Hall picture when the lowest Landau level was only partly filled?

Sandbox Physics · 2026-10-23

Nobel contribution: 1998-1

1. Use a high-mobility heterostructure
2. Cool in a strong magnetic field
3. Record a fractional plateau
4. Test a correlated many-electron state

The plateau establishes fractional Hall transport; the fractional charge of excitations needs a many-body interpretation and additional measurements.

## The 1982 signal appeared inside one Landau level

Tsui, Störmer and Gossard observed a fractional Hall plateau and a longitudinal resistance minimum in a high-mobility gallium-arsenide heterostructure in 1982. The lowest spin-polarized Landau level was only partly occupied.

The original report considered possible ordered states. Laughlin’s 1983 correlated wavefunction supplied a different, influential liquid interpretation, illustrating how observation and explanation developed in sequence.

Sources: [3] [2] [1]

## Interactions create a new collective state

Within a partly filled Landau level, kinetic energy is highly constrained and electron interactions become decisive. Laughlin’s trial state suppresses close approaches and describes an incompressible correlated liquid at selected fractions. It cannot be smoothly replaced by independent electrons filling ordinary bands.

Sources: [2]

## Fractional charge belongs to excitations

The many-body theory predicts localized excitations carrying a fraction of the electron charge. A fractional conductance alone does not measure that charge directly. Later charge-sensitive experiments such as shot-noise measurements provided separate evidence, with their own transport assumptions.

Sources: [1] [2]

## The 1998 contribution keeps its many-body content

The 1998 award recognized the discovery of a new quantum fluid with fractionally charged excitations. Existing integer-band Labs are linked for comparison only. They contain no correlated fractional liquid, so their edge states cannot be relabeled as fractional quasiparticles.

Sources: [1] [2] [4]

Continue with the physics

## Try the related models

### [Magnetic edge spectra](https://sandboxphysics.com/labs/magnetic-edge-spectroscopy/)

Compare bulk bands and edge states in a magnetic lattice.

A single-particle magnetic lattice does not simulate a correlated fractional Hall liquid.

### [Chern insulator](https://sandboxphysics.com/labs/chern-insulator/)

Change a band mass and inspect the gap and topological response.

The band model explains an integer invariant; it has no fractional Hall quasiparticles.

## Sources and reading notes

1. [Störmer: The fractional quantum Hall effect (1998)](https://www.nobelprize.org/uploads/2018/06/stormer-lecture.pdf)

   High-mobility transport and the role of correlations; fractional charge needs evidence beyond a Hall plateau.

2. [Laughlin: Fractional quantization (1998)](https://www.nobelprize.org/uploads/2018/06/laughlin-lecture.pdf)

   The correlated trial state and fractionally charged excitations are a many-body explanation.

3. [Tsui, Störmer and Gossard: Two-dimensional magnetotransport in the extreme quantum limit (1982)](https://doi.org/10.1103/PhysRevLett.48.1559)

   Original fractional Hall plateau and longitudinal minimum; the proposed interpretation evolved after publication.

4. [Nobel Prize in Physics 1998: official award](https://www.nobelprize.org/prizes/physics/1998/summary/)

   Official attribution and award year. The observation or theoretical paper may be much earlier.

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