Mary Scott and
Jianwei (John) Miao/UCLA
The scientists
were able to plot the exact coordinates of nine layers of atoms with
a precision of 19
trillionths of a meter.
Finding will help scientists better understand the
structural properties of materials
(September 21, 2015) Atoms
are the building blocks of all matter on Earth, and the patterns in which they
are arranged dictate how strong, conductive or flexible a material will be.
Now, scientists at UCLA have used a powerful microscope to image the
three-dimensional positions of individual atoms to a precision of 19
trillionths of a meter, which is several times smaller than a hydrogen atom.
Their observations make it possible, for the first time, to
infer the macroscopic properties of materials based on their structural
arrangements of atoms, which will guide how scientists and engineers build
aircraft components, for example. The research, led by Jianwei (John) Miao, a
UCLA professor of physics and astronomy and a member of UCLA’s California
NanoSystems Institute, is published Sept. 21 in the online edition of the
journal Nature Materials.
For more than 100 years, researchers have inferred how atoms
are arranged in three-dimensional space using a technique called X-ray
crystallography, which involves measuring how light waves scatter off of a
crystal. However, X-ray crystallography only yields information about the
average positions of many billions of atoms in the crystal, and not about
individual atoms’ precise coordinates.
“It’s like taking an average of people on Earth,” Miao said.
“Most people have a head, two eyes, a nose and two ears. But an image of the
average person will still look different from you and me.”
Because X-ray crystallography doesn’t reveal the structure
of a material on a per-atom basis, the technique can’t identify tiny
imperfections in materials such as the absence of a single atom. These
imperfections, known as point defects, can weaken materials, which can be
dangerous when the materials are components of machines like jet engines.