Under extremely high pressures, pure vanadium crystals change their shape but do not take up less space as a result, unlike most other elements that undergo phase transitions. The work appears in the February 23 issue of Physical Review Letters.
Led by High Pressure Collaborative Access Team (HPCAT) research scientist Yang Ding, the team* used a diamond anvil cell to subject vanadium crystals to pressures more than 600 thousand times higher than the atmospheric pressure at sea level (which is about one bar). Using the high-resolution HPCAT x-ray facility, the scientists were able to detect that the basic atomic packing units of vanadium crystals had changed from a cube to a rhombohedron, which resembles a cube whose sides have been squashed from squares into diamond shapes.
“Trying to understand why high-pressure vanadium uniquely has the record-high superconducting temperature of all known elements inspired us to study high-pressure structure of vanadium," Ding said. “We had no idea that we would discover a completely new type of phase transition."
The most familiar phase transitions are those between gas, liquid, and solid forms. In general, increasing pressure and decreasing temperature will cause a substance to take up less space and eventually form a solid. But as a result of their atoms packing in closer together at extremely high pressures, some solids undergo further changes in their physical properties and can even change shape, which usually results in a change in volume. But in this respect, vanadium is unique.
Though it is expensive to mine and refine, vanadium is extremely important in the industrial world, where its main use is as a steel additive. Steel that contains vanadium is exceptionally strong and resistant to metal fatigue, making it ideal for kitchen knives that stay sharp almost indefinitely, and jet turbine blades that can withstand high speed and abrasion.
Pure vanadium crystals in cubic form were thought to be able to resist pressures over several million bars. Recent theoretical calculations, however, suggested that pressure could cause unusual electronic interactions in vanadium that would destroy the cubic crystals. Instead, vanadium avoids this collapse by changing to a rhombohedron.
“Although this type of transition was first observed in vanadium, it suggests that we should reexamine many other elements we thought were very stable," Ding explained. “Moreover, the transition provides a new explanation for the continuous rising of superconducting temperature in high-pressure vanadium, and could lead us to the next breakthrough in superconducting materials."
Yang Ding | EurekAlert!
Spinning rugby balls: The rotation of the most massive galaxies
23.05.2018 | Leibniz-Institut für Astrophysik Potsdam
Turning entanglement upside down
23.05.2018 | Universität Innsbruck
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Physics and Astronomy
22.05.2018 | Life Sciences
22.05.2018 | Earth Sciences