Heinrich Rohrer

Heinrich Rohrer was born in Buchs, Switzerland, in 1933. He studied at the Swiss Federal Institute of Technology (ETH Zurich), earning a diploma in 1955 and a doctorate in 1960 under the supervision of Wolfgang Pauli, with a thesis on superconductivity and magnetostriction.¹ After postdoctoral work at Rutgers University in the United States, he joined IBM's Zurich Research Laboratory in 1963.

At IBM Zurich, Rohrer and Gerd Binnig developed the STM in the late 1970s, achieving atomic resolution on silicon surfaces in 1981.² The STM works by scanning a sharp metal tip extremely close to a conductive surface, measuring the quantum tunneling current that flows between them. This current is exponentially sensitive to distance, allowing vertical resolution of a fraction of an angstrom and lateral resolution sufficient to image individual atoms.³ The invention revolutionized surface science and enabled the manipulation of individual atoms, as demonstrated by Don Eigler in 1990.

Rohrer and Binnig received half of the 1986 Nobel Prize in Physics; Ernst Ruska received the other half for his work on electron microscopy.⁴ Rohrer continued at IBM, becoming an IBM Fellow in 1986 and later manager of the physics department. He retired in 1997 but remained active in scientific advisory roles, including promoting nanoscience in developing countries.

Rohrer's early work included studies of magnetostriction and superconductivity, but he also contributed to the development of the scanning near-field optical microscope (SNOM) concept.⁵ He was an avid mountaineer and often compared the STM's tip to a mountain climber's pick. After retirement, he served on the board of the Swiss Nanoscience Institute and advocated for the use of STM in education. A minor planet, 13327 Reuter, is named after him (though the name also honors a German astronomer).⁶

Scanning tunneling microscope (STM)

A microscope that images surfaces at the atomic level by measuring the tunneling current between a sharp tip and the sample.

Tunneling

A quantum mechanical effect where particles pass through a potential barrier they classically cannot surmount.

Nanotechnology

The manipulation of matter on an atomic and molecular scale, typically below 100 nanometers.