The metal-insulator paradox


SmB6 is in the family of materials known as ‘Kondo Insulators’, where the strong interactions between the localized f-electrons and conducting d-electrons causes the electronic structure to rearrange into an insulator.

Remarkably, our experiments found evidence for quantum oscillations arising from the insulating bulk of the material, corresponding to a conduction electron Fermi surface. Tantalising clues suggest an entirely new paradigm where a novel type of itinerant neutral low-energy excitation coexists with a charge gap in a Kondo insulator.

  • Unconventional Fermi surface in an insulator
    Science 349, 287 (2015)
    B. S. Tan, Y. -T. Hsu, B. Zeng, M. Ciomaga Hatnean, N. Harrison, Z. Zhu, M. Hartstein, M. Kiourlappou, A. Srivastava, M. D. Johannes, T. P. Murphy, J. -H. Park, L. Balicas, G. G. Lonzarich, G. Balakrishnan, Suchitra E. Sebastian


Research highlights

Suchitra Sebastian

01223 850481

Siân Dutton

01223 764159

Cavendish Laboratory,

19 J J Thomson Avenue,

Maxwell Center