High-temperature surface state in Kondo insulator U<sub>3</sub>Bi<sub>4</sub>Ni<sub>3</sub>

Journal article

The resurgence of interest in Kondo insulators has been driven by two major mysteries: the presence of metallic surface states and the observation of quantum oscillations. To further explore these mysteries, it is crucial to investigate another similar system beyond the two existing ones, SmB6 and YbB12. Here, we address this by reporting on a Kondo insulator, U3Bi4Ni3. Our transport measurements reveal that a surface state emerges below 250 kelvin and dominates transport properties below 150 kelvin, which is well above the temperature scale of SmB6 and YbB12. At low temperatures, the surface conductivity is about one order of magnitude higher than the bulk. The robustness of the surface state indicates that it is inherently protected. The similarities and differences between U3Bi4Ni3 and the other two Kondo insulators will provide valuable insights into the nature of metallic surface states in Kondo insulators and their interplay with strong electron correlations.

Authors: Broyles, C; Wan, X; Cheng, W; Wu, D; Tan, H

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Association for the Advancement of Science
• Journal: Science Advances
• Volume: 11
• Issue: 12
• Pages: eadq9952
• Publication date: 2025-03-21
• DOI: 10.1126/sciadv.adq9952
• EISSN: 2375-2548
• Pmid: 40117363
• Language: English