Scientists have uncovered hidden complexity in the superconducting behavior of niobium diselenide (NbSe2), a discovery that could improve the design of quantum computers, energy-efficient electronics, and advanced sensors. Understanding how electrons interact inside superconductors may help researchers develop materials and devices with greater control, stability, and precision.
Some of the most important scientific breakthroughs come from examining phenomena researchers believe they already understand. A new study of superconductivity offers a clear example of how closer measurements can reveal an unexpected structure beneath a seemingly simple result.
For decades, physicists have studied superconductors—materials that can carry electric current with zero energy loss. Their unusual properties could support future technologies ranging from highly efficient electronics and quantum computers to sensitive medical imaging systems and advanced sensors.
NbSe2: A Superconductor That Appears Surprisingly Simple
One of the most widely studied superconducting materials is niobium diselenide (NbSe2). When researchers reduce NbSe2 to only a few atomic layers, experiments can make its superconducting behavior appear relatively simple. The material seems to have a single superconducting energy gap, a feature associated with the way electrons pair and move without electrical resistance.
However, scientists suspected that this single-gap model did not fully explain the material’s behavior.
The research was led by PhD student Shahar Simon and M.S. student Maya Klan under the guidance of Professor Oded Milo and Professor Hadar Steinberg at the Raka Institute of Physics and the Center for Nanoscience and Nanotechnology at the Hebrew University of Jerusalem. The findings were reported in Physical Review Letters.
Two Superconducting States Hidden Within One Material
Using highly sensitive tunneling spectroscopy, the researchers found that NbSe2 does not behave as a conventional superconductor governed by only one superconducting order. Instead, the material contains two distinct superconducting orders that interact so strongly they can appear to be a single state.
The researchers observed similar hidden behavior in closely related materials, including TaS2.
“It is like hearing what sounds like one singer, only to discover that the sound is actually produced by a perfectly synchronized duet,” the researchers explained.
The discovery may solve a long-standing mystery in superconductivity. Earlier theoretical models could not fully reproduce the detailed shape of the superconducting energy spectrum recorded in previous experiments.
By applying a more advanced model that incorporates two interacting superconducting orders, the Hebrew University researchers were able to explain their measurements more accurately. The model also helped describe how NbSe2 responds when exposed to an external magnetic field.
Superconductivity Becomes Even More Complex in Thicker Materials
The study suggests that the complexity of superconductivity increases as the material becomes thicker. In bulk NbSe2, researchers believe there may be three interacting superconducting orders, indicating that the material’s superconducting properties are richer and more complex than previously recognized.
Revealing this hidden superconducting structure could help scientists engineer advanced materials and devices with greater precision. As research continues into quantum computing, energy-efficient electronics, and high-performance sensors, a deeper understanding of electron behavior inside superconductors will become increasingly valuable.
Source: www.sciencedaily.com