Physics Spotlight  
Scientists at MIT have found a way to visualize electron behavior beneath a material’s surface. The team’s technique is based on quantum mechanical tunneling, a process by which electrons can traverse energetic barriers by simply appearing on the other side. In this image, researchers show the measured tunneling spectra at various densities, with high measurements in red.

Courtesy of the researchers Scientists at MIT have found a way to visualize electron behavior beneath a material’s surface. The team’s technique is based on quantum mechanical tunneling, a process by which electrons can traverse energetic barriers by simply appearing on the other side. In this image, researchers show the measured tunneling spectra at various densities, with high measurements in red.
Courtesy of the researchers

A new window into electron behavior

Scientists invent technique to map energy and momentum of electrons beneath a material’s surface.

Jennifer Chu | MIT News Office
November 16, 2017

For the first time, physicists have developed a technique that can peer deep beneath the surface of a material to identify the energies and momenta of electrons there.

The energy and momentum of these electrons, known as a material’s “band structure,” are key properties that describe how electrons move through a material. Ultimately, the band structure determines a material’s electrical and optical properties.

The team, at MIT and Princeton University, has used the technique to probe a semiconducting sheet of gallium arsenide, and has mapped out the energy and momentum of electrons throughout the material. The results are published today in the journal Science.
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