Discovered by Klaus von Klitzing in 1980, the QHE occurs in two-dimensional electron systems, such as those found in graphene or semiconductor heterostructures. When a magnetic field is applied perpendicular to the plane of the electron system, it quantizes the Hall resistance into discrete levels. This quantization is represented by the equation RH = h/e2 * 1/ν, where h is Planck's constant, e is the electron charge, and ν is an integer (for the Integer Quantum Hall Effect) or a fraction (for the Fractional Quantum Hall Effect).
