Evolution of the low energy electronic states in Sm_xLa_(1-x)B₆ studied by ARPES

In the recent years, the interplay between topological orders and electronic correlations has attracted the attention of the scientific community. Theoretical works propose SmB₆ as a Topological Kondo Insulator in which topologically protected surface states lie within the bulk band gap stemming from the hybridization of localized f-electrons with conduction electrons [1, 2]. However, experimental evidences of the bulk origin of the in gap states have been reported; in particular Z.-H. Zhu et al. observed non-topological surface states originating from B-2p dangling bonds on a polar surface [3]. In order to overcome the complexity in the theoretical interpretations of the ground state of SmB₆, we use ARPES to study a wide range of Sm_xLa_(1-x)B₆ samples. LaB₆ has the same crystal structure of SmB₆ and presents qualitatively the same features in the electronic structure, but the lack of f-electrons leads to a metallic ground state. Here we report on the evolution of the low energy electronic states in SmB₆ as a function of electronic correlations by gradually varying the stoichiometry of Sm_xLa_(1-x)B₆ compounds.


[1] M. Dzero et al., Phys. Rev. Lett. 104, 106408 (2010)
[2] M. Dzero et al., Phys. Rev. B 85, 045130 (2012)
[3] Z.-H. Zhu et al., Phys. Rev. Lett. 111, 216402 (2013)