scanning tunneling microscope

scanning tunneling microscope

n.

A microscope that scans the surface of a sample with a beam of electrons, causing a narrow channel of tunneling electrons to flow between the sample and the beam, and producing three-dimensional images of atomic topography and structure.

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scanning tunneling microscope

A microscope used to make images of individual atoms on the surface of a metal. The microscope has a probe with a small voltage applied to it ending in a tiny sharp tip (ideally consisting of one atom) that is moved close the material's surface. Quantum tunneling of electrons between tip and the metal provides a small current, and that current is held constant by varying the distance between the tip and the material's surface atoms. As the probe is moved across the surface, a three-dimension image of the surface is formed, based on the continual adjustments made to the height of the tip to keep the electron flow constant.