[Research Highlights Vol.41] Evidence of A New Type of Quantum Effect

The quantum Hall effect (QHE) is a phenomenon that can occur in a two-dimensional electron gas — a system in which electrons can move in a plane but not perpendicularly to it. Such a system is typically realized in a heterostructure of thinly stacked layers of different semiconductors. The QHE is usually observed at low temperatures and high magnetic fields; it manifests itself through the quantization of values of the electronic conductance (the inverse of resistance) — the values are integer or particular fractional multiples of a fundamental conductance quantum.