“We have discovered a material that opens a new era for humanity.” Strong words from Sukbae Lee and Ji-Hoon Kim of the Quantum Energy Research Center in South Korea, the team of physicists who ha recently announced what could be a sensational discovery. It is a mixture of sulfur and lead powders which, combined togheter with oxygen and brought to high temperatures, would have led to the creation of LK-99, a material that behaves as a superconductor at room pressure and temperature.
South Korean researchers say LK-99 can be produced with a cooking process that combines the minerals lanarkite (Pb₂SO₅) and copper phosphide (Cu₃P). According to them, the resulting material shows two important evidences of superconductivity: zero resistance and magnetic levitation.
If you’ve ever had an MRI, you’ve stood inside a large electromagnet made of superconducting wire. The resistance-free flow allows you to create a very strong magnetic field without heating up or consuming a huge amount of energy.
In superconductors, electrons move without facing any resistance. Superconducting wires are capable of transmitting electricity without losing energy, and superconducting magnets can levitate trains and contain plasmas in fusion reactors.
The phenomenon of superconductivity was discovered at the beginning of the 20th century by Kamerlingh Onnes, starting from the observation of a wisp of mercury at -268.96° Celsius. This, below the critical temperature threshold, transitioned from the state of insulator to the state of conductor. More precisely it transformed into a conductor with practically zero electrical resistance. A superconductor indeed.
The other great peculiarity of superconductors consists in the presence within them of a zero magnetic field. Therefore, if suspended above a magnet, they levitate, expelling the magnetic field and generating surface currents. Due to this particular ability, called the Meissner effect, superconductors are widely used within nuclear particle accelerators.
The discovery earned him the Nobel Prize in 1913: it is the perfect conductor, which does not overheat when current passes and therefore has no Joule effect. No need to say that this discovery led to many innovations in the field of technology.
The small side effect, which has hindered their widespread use capable of revolutionizing our everyday lives, is that bringing them to superconducting temperature is extremely expensive. That’s why the discovery of LK-99 sound so important: it does not have to be brought to particular temperatures, spending a fortune, for it to exercise its superconducting capabilities. It behaves as a superconductor at ambient pressure and temperature.
Skepticism on the topic
As the discovery spread, skepticism about it did not take long to follow. In fact, in the past other research teams announced similar discoveries, claiming to have found a material with the same characteristics, but subsequent tests proved them wrong.
The South Korean researchers proposed a plausible theory to explain how the material used could show evidence of superconductivity at room temperature, but were unable to provide clear experimental evidence. The data presented in the documents in fact appear inconclusive.
In a video demonstration, researchers place a piece of LK-99 on a magnet. One edge of LK-99’s flat disc rises, but the other edge appears to maintain contact with the magnet.
However, a superconductor is expected to exhibit complete levitation, maintaining a fixed position relative to the magnet. The behavior we see in the video could be due to imperfections in the sample, meaning that only part of the sample becomes superconducting.
“They look like amateurs,” says Michael Norman, a theorist at Argonne National Laboratory. “They don’t know much about superconductivity and the way they presented some of the data is suspicious.” The main reasons that arouse skepticism according to Norman are the following:
- The undoped material, lead apatite, used in the experiment is not a metal but rather a non-conducting mineral. We quickly realize that this is an unpromising starting point for creating a superconductor.
- Lead and copper atoms have similar electronic structures, so replacing the copper atoms with some of the lead atoms should not greatly affect the electrical properties of the material.
- Lead atoms are very heavy, which should suppress vibrations and make it harder for electrons to pair.
The team has released two scientific papers on the subject on the ArXiv platform and now their work must be subjected to scientific review. The researchers also extended the invitation to all their colleagues around the world, asking them to replicate the experiment.
If true, the discovery would be one of the greatest ever in condensed matter physics: it could solve the problem of the energy crisis, revolutionizing the energy generation and transmission system. It would also have an enormous impact on the transport system, the information system and other sectors of technology, starting a new technological era (very similar to the one dreamed on the big screen by the authors of that cinema that wants to anticipate the future, showing us perfectly levitating vehicles efficient, before the technology necessary for their realization is available).
It’s still too early to celebrate, but if LK-99 really worked our future would be completely redesigned.
Long story short
“World-changing” LK-99 Superconductor