Klaus von Klitzing
active c. 1943, Schroda, Germany (now Środa Wielkopolska, Poland)
German physicist who discovered the integer quantum Hall effect — resistance quantized in exact multiples of h/e² — revolutionizing metrology and condensed matter.
Educated at Braunschweig and Würzburg, von Klitzing was measuring Hall resistance in silicon MOSFETs at the high-field laboratory in Grenoble when, on the night of 4–5 February 1980, plateaus appeared at exactly h/e² divided by an integer — reproducible to parts per billion. The quantized resistance, now defining the ohm, opened the field of topological condensed matter physics, later extended to the fractional effect by Tsui, Störmer and Laughlin.
Nobel-winning work
Von Klitzing's 1985 Nobel Prize recognized his discovery that in a two-dimensional electron gas at low temperature and high magnetic field, the Hall resistance does not vary smoothly but locks onto exact plateaus at R_H = h/(νe²) with integer ν.
The quantization is universal — independent of sample, material or disorder — because it counts filled topological Landau levels. The von Klitzing constant R_K = h/e² ≈ 25 812.807 Ω became the resistance standard in 1990, and since the 2019 SI redefinition the effect ties the ohm directly to the Planck constant and the elementary charge.
Workplaces: Max Planck Institute for Solid State Research, Stuttgart
Germany