A real picture of an atom is not a photograph in the everyday sense. Atoms are typically around 100 picometers across, far too small to see with light, so every atomic image is built from electrons or a probe tip scanning a surface. The sharpest picture of atoms so far comes from a Cornell University team, whose 2021 electron images were limited only by the atoms’ own thermal jiggling.
Key facts about pictures of atoms
- Size of an atom: typically around 100 picometers (a tenth of a nanometer) across (Wikipedia)
- Why light cannot do it: ordinary microscopes use light waves that are far larger than an atom
- Breakthrough tool: the scanning tunneling microscope, developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich
- Nobel Prize: Binnig and Rohrer shared the 1986 Nobel Prize in Physics for it
- Record resolution: electron ptychography at Cornell, set in 2018 and roughly doubled again in 2021 (Cornell Chronicle)
- Famous atom movie: IBM’s 2013 stop-motion film A Boy and His Atom, made by moving carbon monoxide molecules with a scanning tunneling microscope
Understanding atom imagery
Capturing images of atoms, the building blocks of matter, pushes the limits of technology. Each method below produces a different kind of atomic image, and none of them works like a camera.
Basics of atoms and electron microscopy
Atoms are the smallest units of matter that keep the identity of an element. They are made of protons, neutrons and electrons. Electron microscopes use a beam of electrons instead of light. Because electrons have a much shorter wavelength than light, they can reveal how atoms are arranged inside a material.
Scanning tunneling microscopes: the first atomic pictures
A scanning tunneling microscope (STM) moves an extremely sharp metal tip just above a conducting surface. A tiny electric current flows across the gap, and that current changes as the tip passes over each atom. Recording the current point by point builds a map of the surface, atom by atom.
The STM was developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich, who won the 1986 Nobel Prize in Physics for it. The same tip can also push atoms and molecules around. IBM used that trick for A Boy and His Atom, a one-minute film released in 2013, whose frames were made from carbon monoxide molecules magnified 100 million times.
Atomic force microscopes
An atomic force microscope (AFM) feels a surface with a tiny tip on a flexible beam, rather than measuring a current. It works on materials that do not conduct electricity, and since the 1990s it has reached true atomic resolution.
Challenges in capturing images of atoms
Capturing clear images of individual atoms is hard. Atoms vibrate constantly, which blurs the image. The resolution of an electron microscope also depends on the quality of the electron beam and its detectors. In thicker samples, electrons bounce around several times before leaving, which scrambles the picture.
The highest resolution picture of atoms
In 2018, a Cornell team led by David Muller combined a powerful detector with a computer method called electron ptychography and tripled the resolution of a state-of-the-art electron microscope, according to the Cornell Chronicle.
Ptychography scans a beam across the sample and records a diffraction pattern at each spot. Software then works backward from those overlapping patterns to rebuild the image, correcting for errors in the lenses.
In 2021 the same team beat its own record by a factor of two, using the electron microscope pixel array detector (EMPAD) and better 3D reconstruction algorithms. Their image of a praseodymium orthoscandate (PrScO3) crystal, magnified 100 million times, is so sharp that the only blur left is the thermal motion of the atoms themselves. The work was published in Science in May 2021. Scientific American and New Scientist covered the result.
The method also solves an old problem: undoing the multiple scattering of electrons inside a sample, which had long blocked sharper images of thicker materials.
Other ways to see single atoms
Researchers have also detected a single atom with X-rays, an approach that could help identify individual atoms by their chemistry.
Why atomic images matter
Seeing exactly where atoms sit helps scientists understand and design new materials, such as semiconductors. It also lets researchers spot single missing or extra atoms that change how a material behaves.
Frequently asked questions
Is there a real picture of an atom?
Yes. Scanning tunneling microscopes, atomic force microscopes and electron microscopes all produce real images of individual atoms. They are built from measured signals, such as electric current or scattered electrons, rather than light.
Can you see an atom with a regular microscope?
No. Light waves are much larger than an atom, which is typically around 100 picometers across, so an ordinary light microscope cannot resolve one.
What does an atom look like in a picture?
In most atomic images, each atom shows up as a fuzzy round blob or bright spot, arranged in neat rows in a crystal. The colours are added by scientists to make the data easier to read.
What is the highest resolution image of atoms?
The Cornell team led by David Muller set the record with electron ptychography, first in 2018 and then by doubling it in 2021. Their 2021 images of a praseodymium orthoscandate crystal are limited only by the vibration of the atoms themselves.
How do scientists take pictures of atoms?
They scan a sharp tip over a surface and record a current (scanning tunneling microscope) or a force (atomic force microscope), or they fire electrons through a thin sample and rebuild the image by computer (electron microscopy and ptychography).