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Klaus von Klitzing coauthored the discovery of precisely quantized Hall resistance in a silicon device containing a two-dimensional electron gas. In a strong magnetic field, resistance plateaus followed values set by $h/e^2$ and an integer filling index, rather than changing smoothly with every microscopic device parameter. The 1980 work used the reproducibility for a precision-constants measurement. The integer quantum Hall effect thus connects a collective electronic state with a robust electrical reference.^[ref]

A physicist.^[ref]

Awarded to Klaus von Klitzing for discovering the quantum Hall effect.^[ref]

Klaus von Klitzing, G. Dorda and M. Pepper reported a silicon MOSFET measurement in 1980. Its gate controlled an semiconductor inversion layer; transverse contacts measured the Hall voltage and separate longitudinal contacts measured dissipation. One sweep held $B=18\mathrm{T}$, $T=1.5\mathrm{K}$ and $I=1\mu \mathrm{A}$ fixed while varying gate voltage. Hall plateaus accompanied small longitudinal voltages. Device-geometry comparisons and high-input-impedance voltage measurements helped test whether contact placement or electrical loading produced the result.^[ref]

This original functional diagram separates transverse and longitudinal readouts; it does not reproduce the historical device's dimensions. The gate inset explains how a field-effect transistor provides an adjustable two-dimensional electron gas. A longitudinal voltage close to zero is a useful check because accidental longitudinal separation between Hall contacts can otherwise contaminate the transverse measurement.