Skip to main content
eScholarship
Open Access Publications from the University of California

UC Irvine

UC Irvine Previously Published Works bannerUC Irvine

Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4

  • Author(s): Nakatsuji, S;
  • Kuga, K;
  • Machida, Y;
  • Tayama, T;
  • Sakakibara, T;
  • Karaki, Y;
  • Ishimoto, H;
  • Yonezawa, S;
  • Maeno, Y;
  • Pearson, E;
  • Lonzarich, GG;
  • Balicas, L;
  • Lee, H;
  • Fisk, Z
  • et al.

Published Web Location

https://doi.org/10.1038/nphys1002Creative Commons 'BY' version 4.0 license
Abstract

A long-standing question in the field of superconductivity is whether pairing of electrons can arise in some cases as a result of magnetic interactions instead of electron-phonon-induced interactions as in the conventional Bardeen-Cooper-Schrieffer theory. A major challenge to the idea of magnetically mediated superconductivity has been the dramatically different behaviour of the cerium and ytterbium heavy-fermion compounds. The cerium-based systems are often found to be superconducting, in keeping with a magnetic pairing scenario, but corresponding ytterbium systems, or hole analogues of the cerium systems, are not. Despite searches over two decades there has been no evidence of heavy-fermion superconductivity in an ytterbium system, casting doubt on our understanding of the electron-hole parallelism between the cerium and the ytterbium compounds. Here we present the first empirical evidence that superconductivity is indeed possible in an ytterbium-based heavy-fermion system. In particular, we observe a superconducting transition at Tc=80 mK in high-purity single crystals of YbAlB 4 in the new structural β phase. We also observe a novel type of non-Fermi-liquid state above Tc that arises without chemical doping, in zero applied magnetic field and at ambient pressure, establishing β-YbAlB4 as a unique system showing quantum criticality without external tuning. © 2008 Macmillan Publishers Limited. All rights reserved.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View