Scientists Discover Two Superconducting States Hiding as One
- Physicists at the Hebrew University of Jerusalem have discovered that ultrathin niobium diselenide and related materials contain two distinct superconducting states so strongly coupled they appear as a...
- For decades, researchers studying superconductors focused on materials like niobium diselenide, commonly known as NbSe2.
- Traditional theories failed to accurately reproduce the detailed shape of the superconducting energy spectrum observed in laboratory tests over the years.
Physicists at the Hebrew University of Jerusalem have discovered that ultrathin niobium diselenide and related materials contain two distinct superconducting states so strongly coupled they appear as a single energy gap. Published in Physical Review Letters, the finding resolves a long-standing physics puzzle regarding how electrons pair up to carry electrical current with zero energy loss.
A Hidden Duet Within Ultrathin Superconductors
For decades, researchers studying superconductors focused on materials like niobium diselenide, commonly known as NbSe2. When scientists reduced the material to just a few atomic layers, initial experiments indicated straightforward superconducting behavior governed by a single energy gap, which reflects how electrons form pairs to move without resistance.
Cracking the Spectrum Puzzle in NbSe2
Traditional theories failed to accurately reproduce the detailed shape of the superconducting energy spectrum observed in laboratory tests over the years. According to the Hebrew University team, researchers had reason to suspect that the simple single-gap model was incomplete.
Using highly sensitive tunneling spectroscopy measurements, the researchers determined that NbSe2 does not rely on a single superconducting order. Instead, the material hosts two different superconducting orders that interact so strongly they mimic a unified state.
The study was led by doctoral student Shahar Simon and master’s student Maya Klang, under the guidance of Prof. Oded Millo and Prof. Hadar Steinberg from the Racah Institute of Physics and the Center for Nanoscience and Nanotechnology.
It’s a bit like listening to what sounds like a single singer, only to discover it’s actually a perfectly synchronized duet.
Hebrew University Research Team
Expanding the Physics Landscape to Tantalum Disulfide
The researchers also identified the same concealed multi-order behavior in a closely related material, tantalum disulfide, or TaS2, according to the published findings. By applying an advanced model incorporating two distinct superconducting orders, the team successfully matched experimental measurements more accurately than previous theories, including predictions of how the materials react when exposed to magnetic fields.
Furthermore, the data points to even greater complexity in thicker samples. According to the study, bulk NbSe2 may feature three interacting superconducting orders, suggesting that superconductivity in these transition metal dichalcogenides is structurally richer than previously understood.
Engineering the Next Generation of Quantum Devices
Uncovering this hidden internal structure could eventually allow engineers to design superconducting materials and devices with greater control and precision.
As laboratories worldwide pursue quantum computers, ultra-efficient electronics, and advanced sensors, a detailed grasp of electron behavior inside superconductors will become increasingly vital for device architecture.