Donald M. Eigler (March 23, 1953) is an American physicist associated with the IBM Almaden Research Center, who is noted for his achievements in nanotechnology.

[1] Eigler's 1989 research, along with Erhard K. Schweizer, involved a new use of the scanning tunneling microscope, which had been invented in the mid 1980s by Gerd Binnig and Heinrich Rohrer, also of IBM.

The microscope had previously been used for atomic-resolution imaging, but this was the first time it had been used as an active technique, to precisely position individual atoms on a surface.

The technique requires vacuum conditions and ultra-cold temperatures achieved by liquid helium cooling, and was featured on the cover of the journal Nature.

[2][3] Eigler's 2002 research, along with Andreas J. Heinrich, used a cascade of collisions of carbon monoxide molecules to perform logic operations.