Competing electronic ground states in CeRh2As2

Published February 10, 2026

Magnetic fields of up to 73 T were used to provoke electrons in the compound CeRh₂As₂ into a frenzy of very varied and unexpected behavior. These experimental results reveal that the electrons inhabit an unstable quantum-mechanical environment, resulting in unusual properties that may find applications in future electronic devices.

What is the finding

Researchers discovered that electrons in CeRh₂As₂ can abruptly change their quantum behavior depending on magnetic‑field direction and strength. With magnetic field perpendicular to the crystal layers, electrons suddenly localize on cerium (Ce) atoms at high fields.

With the field within the layers, electrons instead organize into three distinct, wave‑like ordered states. The boundaries between these states shift in precise, characteristic ways as field and temperature are varied. This demonstrates that multiple electronic ground states are in direct competition within the same material.

Why is this important?

These results show CeRh₂As₂ exists in a delicately balanced quantum regime where small changes in conditions push electrons into entirely different states.

This instability helps explain the material’s highly unusual superconductivity, which coexists with and competes against other quantum phases. Understanding this balance is critical for engineering superconductors and quantum materials with tunable properties. Insights gained here may help guide the design of future quantum‑computing or quantum‑electronic devices, potentially operating at higher temperatures.

Who did the research?

Joanna Blawat¹, Grzegorz Chajewski², Daniel Gnida², John Singleton¹, Oscar Ayala Valenzuela¹, Dariusz Kaczorowski², Ross McDonald¹

¹National MagLab, ²Institute of Low Temperature and Structure Research, Polish Academy of Sciences

Why did they need the MagLab?

This work was only possible using the unique capabilities of the National High Magnetic Field Laboratory. Focused Ion Beam lithography (co‑located with the Pulsed‑Field Facility) enabled fabrication of microscopic CeRh₂As₂ devices. Ultra‑high magnetic fields (up to 73 tesla)—the strongest available in the U.S.—were essential to access the competing quantum states. A custom 3D‑printed goniometer allowed precise rotation of samples while reaching temperatures as low as 0.5 K. Together, these capabilities reveal how extreme magnetic fields can uncover and control fragile quantum states crucial for next‑generation technologies.

Details for scientists

View or download the expert-level Science Highlight, Competing electronic ground states in CeRh₂As₂
Read the full-length publication, Competing Electronic Ground States in the Heavy-Fermion Superconductor CeRh₂As₂, in Physical Review X

Funding

This research was funded by the following grants: K. M. Amm (NSF DMR-2128556); J. Blawat, R. McDonald (CATS EFRC DEAC02-07CH11358); J. Singleton (DOE BES “Science of 100 T”)

For more information, contact Neil Harrison.