Neutral Fermi surfaces in Mixed Valent Kondo Insulators: Majorana Hubbard Operators*

The development of slave particle approaches provides a way to explore different patterns of operator fractionalization in strongly correlated systems. The recent observation of quantum oscillations in mixed valent SmB₂ has raised the possibility of neutral Fermi surfaces in this material[1-4]. This motivates a search for a representation of the Hubbard operator in terms of Majorana, rather than Dirac fermions. In this talk I will describe how this can be achieved and using the method, discuss the prospects for a two-phase description of SmB₆, in terms of a competition between a fully gapped strong topological insulator and a strange dielectric.



[1] P. Coleman, E. Miranda, and A. Tsvelik, Physica B: Condensed Matter 186-188, 362 (1993).
[2] G. Baskaran, ArXiv arXiv:1507.03477.
[3] Onur Erten, Po-Yao Chang, Piers Coleman, Alexei M. Tsvelik, Phys. Rev. Lett., 119, 057603 (2017).
[4] Debanjan Chowdhury, Inti Sodemann and T. Senthil, Nature Communications, 9, 1766 (2018).