For centuries, humanity has searched for ways to peer deeper into nature, to see not just the things around us but the building blocks that create them. With the invention of the microscope, entire hidden worlds were revealed—from the intricate forms of cells to the teeming activity of microorganisms. Later, electron microscopy pushed the boundaries further, allowing scientists to see the architecture of matter down to the level of atoms themselves.
Now, researchers at the University of California, Irvine, in collaboration with international teams from Sweden and China, have taken another groundbreaking step forward. For the first time in history, scientists have directly imaged the vibrations of atoms—known as phonons—in specific directions at the atomic scale. This discovery opens an entirely new way of understanding the invisible dance of matter, one that could transform technologies ranging from semiconductors to quantum computers.
The Secret Rhythms of Matter
At first glance, solid materials seem static, rigid, and unmoving. But on the atomic level, nothing is still. Every atom is in constant motion, jiggling, oscillating, and vibrating against its neighbors. These vibrations ripple through crystals in collective waves known as phonons, and though we cannot see them with the naked eye, they are among the most important forces shaping the properties of matter.
The way these vibrations occur is not uniform. In many crystalline materials, atoms move differently depending on the direction—this property is called vibrational anisotropy. Like wind blowing in different strengths depending on which way you face, the vibrations of atoms vary depending on their orientation in the lattice. These tiny differences can dictate how a material behaves: how it conducts heat, how it responds to electric fields, and even whether it can become a superconductor.
Understanding vibrational anisotropy is like discovering the rhythm of matter’s heartbeat. If scientists can measure it precisely, they can tune it, controlling the properties of materials for advanced technologies. Until now, however, these subtle directional vibrations were almost impossible to study directly.
A Revolutionary Microscope
The breakthrough comes from a powerful new electron microscopy technique known as momentum-selective electron energy-loss spectroscopy, or EELS. Traditional electron microscopes can show us where atoms are, but this method adds a new dimension: it captures their motions, their tiny shivers and shakes, at astonishing levels of detail.
By directing beams of electrons through crystals and measuring how those electrons lose energy, the researchers can reconstruct the vibrational patterns of atoms in specific directions. This makes it possible to map anisotropy not just across an entire crystal but atom by atom, direction by direction, with unprecedented precision.
The team tested their approach on two perovskite oxides—strontium titanate and barium titanate. These materials are more than laboratory curiosities; they are workhorses of modern technology, prized for their unique electrical, optical, and ferroelectric properties. By focusing on their phonons, the scientists uncovered striking contrasts in the way atoms vibrated, depending not only on the crystal direction but also on the type of atom and its precise location in the lattice.
Shaking the Foundations of Old Models
What the researchers observed went far beyond expectations. For decades, many models of lattice vibrations have assumed that phonons spread out evenly, like waves across a calm pond. But this new work revealed something much richer: the vibrations are not uniformly distributed. Instead, they fluctuate at the atomic level, shifting depending on which elements and sites are involved.
As Professor Xiaoqing Pan, the study’s co-author and director of UC Irvine’s Materials Research Institute, explained, the measurements they obtained are “totally different” from those predicted by integrated, crystal-wide averages. This means that long-standing simplifications in physics and materials science may now need to be reconsidered. The atomic world is more intricate than previously thought, and phonons—once described only in broad strokes—can now be painted with atomic-scale detail.
Unlocking the Future of Materials
The implications of this breakthrough stretch far and wide. Phonons are not just abstract vibrations; they shape the very essence of materials. In semiconductors, phonons influence how efficiently electrons flow, impacting computer chips and electronic devices. In thermoelectric materials, they determine how heat moves, a crucial factor in energy efficiency. In ferroelectrics, they drive the alignment of electric dipoles, enabling memory storage and sensing applications. And in superconductors, the interactions between electrons and phonons help decide whether a material can conduct electricity with zero resistance.
By directly imaging vibrational anisotropy, scientists now have a powerful new tool for tailoring materials at the most fundamental level. Engineers could design crystals where vibrations are channeled in ways that optimize performance, leading to faster electronics, more efficient energy devices, and even breakthroughs in quantum technology.
Senior co-author Ruqian Wu, professor of physics and astronomy at UC Irvine, noted that the team’s findings match closely with theoretical predictions, providing a new foundation for exploring some of the most critical questions in condensed matter physics. These include the mechanisms of ferroelectric transitions, the origins of ferroelectricity itself, and the mysterious role of oxygen atoms in high-temperature superconductivity.
A Global Effort for a Shared Dream
This achievement is not the work of one laboratory but the result of international collaboration. Scientists from Uppsala University in Sweden and from Nanjing University and the Ningbo Institute of Materials Technology and Engineering in China joined forces with the UC Irvine team, combining expertise and innovation to make the impossible possible.
Together, they have shown that even in an age where science seems to have mapped so much of the natural world, there are still hidden landscapes waiting to be revealed—vibrational landscapes that govern the behavior of matter itself.
A New Chapter in Materials Science
This is more than a scientific milestone; it is the opening of a new chapter. By giving us a way to “see” vibrations, researchers have pulled back the curtain on one of the universe’s most fundamental processes.
It is a reminder that the world is alive with motion, even in its quietest and most solid forms. Every atom hums with energy, and now, for the first time, we can watch that hum play out in real time, in real space, at the scale of the building blocks of matter.
The ability to map these vibrations with such precision is not just a technical achievement; it is a poetic one. It brings us closer to the truth that all matter dances to hidden rhythms—and that by listening carefully, we may learn not only how to understand those rhythms but how to orchestrate them, shaping the future of technology and deepening our understanding of the universe itself.
More information: Xingxu Yan et al, Atomic-scale imaging of frequency-dependent phonon anisotropy, Nature (2025). DOI: 10.1038/s41586-025-09511-z
