Heinrich Rohrer

Heinrich Rohrer, born in 1933, Swiss physicist and co-winner of the 1986 Nobel Prize for physics for his invention of the scanning tunneling microscope, a new type of powerful microscope capable of detecting images at the atomic level. Rohrer shared the prize with German physicists Gerd Karl Binnig and Ernst August Friedrich Ruska.

Rohrer was born in Buchs, Sankt Gallen, Switzerland, and studied at the Swiss Federal Institute of Technology, where he earned his Ph.D. degree in 1960. He joined the IBM Research Laboratory near Zürich, Switzerland, in 1963. There, he and Binnig turned their attention to an experiment that required the study of a microscopic surface. In so doing they created a new type of microscope.

The scanning tunneling microscope is based on the wavelike property of electrons. The microscope has a sharp probe that moves near the sample's surface in a vacuum, and emits electrons. The electrons tunnel, or flow through the vacuum, from the probe's tip to the sample's surface. The microscope records any change in distance between the probe and the sample—even as small as the diameter of a single atom. By moving the probe in a sweeping motion, a three-dimensional image of the sample can be produced. This image shows detail not possible with any other kind of microscope. It can reveal the surface of a material at the atomic level and also provide information about its atomic composition. The scanning tunneling microscope has been used to study biological samples, to analyze industrial materials (such as superconductors), and to test miniaturized electronic circuits.