Explore the secrets of high-temperature superconductors! Physicists caught a mysterious wave

[ Instrument R & D of Instrument Network ] Physicists finally caught the superconductor wave. The first direct evidence of the physical phase of density waves helps to reveal the physical principles of mysterious high-temperature superconductors. Superconductors conduct electricity without resistance at surprisingly high temperatures.

The researchers reported in the April 1 issue of Nature that this wave was detected with a scanning tunneling electron microscope.

Physicists once suspected that there are pairs of density waves in these materials, and previous experiments have hinted at their existence. But without direct evidence, scientists cannot further understand these materials.

"It is very important to study and prove that this stage is not only possible, but indeed exists," said Eun-Ah Kim, a theoretical physicist at Cornell University who did not participate in this work.

When high-temperature superconductors appeared in the 1980s, physicists were amazed.

This material is called copperate because it contains copper. It can conduct electricity without resistance at temperatures higher than most superconductors (about 100 Kelvin, about -173 degrees Celsius) or higher.

Although still very cold, such temperatures are much easier to achieve than the temperatures near absolute zero required by many superconductors.

The discovery of these materials makes people have high hopes that room temperature superconductors will be found soon, which may lead to the emergence of new technologies, such as power grids, maglev trains and powerful supercomputers that greatly improve energy efficiency.

However, a few decades later, a room temperature superconductor has not yet appeared. More importantly, scientists have not fully understood the physical principles that make these materials so special.

In particular, "We want to understand the microscopic mechanism of how superconductivity occurs in these materials," said Kazuhiro Fujita, a physicist at Brookhaven National Laboratory in Upton, New York.

In superconductors, electrons form a pair, called Cooper pairs. This partnership allows them to pass through materials without resistance.

In these materials, scientists observed a gap in electron energy rather than a continuous spectrum.

Physicists predict that in high-temperature superconductors, the gap of electron energy will periodically change on the surface of the material, forming a strange wave.

Fujita and his colleagues detected this wave on the surface of a superconducting compound (a bismuth-based copper oxide) using a scanning tunneling microscope.

The research team reported that the energy gap periodically changes in the form of waves on the surface of the material, as predicted.

"This is actually a direct measurement of the density wave component," said Eduardo Fradkin, a theoretical physicist at the University of Illinois at Urbana-Champaign.

"This is a very exciting experiment."

This new result can help scientists better understand this stage because it clarifies how these materials behave during the heating process.