NIST: Using a groundbreaking new technique at the National Institute of Standards and Technology (NIST), an international collaboration led by NIST researchers has revealed previously unrecognized properties of technologically crucial silicon crystals and uncovered new information about an important subatomic particle and a long-theorized fifth force of nature. By aiming subatomic particles known as neutrons at silicon crystals and monitoring the outcome with exquisite sensitivity, the NIST scientists were able to obtain three extraordinary results: the first measurement of a key neutron property in 20 years using a unique method; the highest-precision measurements of the effects of heat-related vibrations in a silicon crystal; and limits on the strength of a possible “fifth force” beyond standard physics theories.
In a regular crystal such as silicon, there are many parallel sheets of atoms, each of which forms a plane. Probing different planes with neutrons reveals different aspects of the crystal. The researchers report their findings in the journal Science. To obtain information about crystalline materials at the atomic scale, scientists typically aim a beam of particles (such as X-rays, electrons or neutrons) at the crystal and detect the beam’s angles, intensities and patterns as it passes through or ricochets off planes in the crystal’s lattice-like atomic geometry. That information is critically important for characterizing the electronic, mechanical and magnetic properties of microchip components and various novel nanomaterials for next-generation applications including quantum computing. A great deal is known already, but continued progress requires increasingly detailed knowledge.