Taking Tunneling Spectroscopy to new Extremes: Revealing Superconducting Symmetries in Sulfur at Ultra High Pressures

Published November 14, 2024

Left: A change of differential conductance occurs in response to applied voltage. Right: The tunneling circuit formed on the tip of the diamond anvil press.

Researchers from the Max-Planck Institute for Chemistry and the National High Magnetic Field Laboratory at Los Alamos developed a groundbreaking method to perform tunneling spectroscopy measurements under ultra-high pressures, revealing superconducting properties in elemental sulfur. This advancement allows for the detailed study of materials that exhibit superconductivity under extreme pressures, which is essential for the development of next-generation superconductors.

What did scientists discover?

Scientists from the Max-Planck Institute and the National High Magnetic Field Laboratory made an exciting discovery by using a technique called tunneling spectroscopy under extremely high pressures for the very first time. They measured how certain materials – in this case Elemental sulfur - become superconductors, meaning they allow electricity to flow without resistance. By cooling the materials under pressure, they observed the exact energy levels at which electrical resistance disappeared, showing the transition to a superconducting state. (Fig. 1).

Why is this important?

This discovery is important because many materials show improved superconducting properties, like working at higher temperatures and in stronger magnetic fields, when exposed to high pressure. Some materials, like hydrides, which hold the record for the highest superconducting temperatures, only become superconductors under extremely high pressure (over 1 million times atmospheric pressure). This study gives scientists a way to explore these materials´ properties in detail for the first time, helping to design better superconductors in the future.

Who did the research?

F. Du¹, F. F. Balakirev², V. S. Minkov¹, G. A. Smith², B. Maiorov², P. P. Kong¹, A. P. Drozdov¹, and M. I. Eremets¹

¹ Max Planck Institute for Chemistry, Mainz; ²National MagnLab, Los Alamos National Laboratory, Los Alamos

Why did they need the MagLab?

Scientists at the MagLab created new tools and methods to study superconductors under much higher pressures than ever before—up to 1.6 million atmospheres, compared to the previous limit of 3,000 atmospheres. This breakthrough brings research closer to pressures found near the Earth's core, pushing the boundaries of superconducting research in extreme conditions..