The topological origin of in-gap surface states of mixed-valent SmB₆, a candidate topological Kondo insulator, is currently being debated. In addition, there exist distinct discrepancies in the bulk electronic structure between DFT-based theory, ARPES, recent NIXS determination of the unoccupied f-hole symmetry [1], and the existence of low temperature dHvA oscillations [2,3]. Here we explore the role of f-p hybridization in assisting f-d hybridization in the formation of an insulating gap in its f-electronic structure. In a five-band model, the relative phase of f-d and f-p hybridizations allows tuning of the f-band structure between DFT-like and ARPES-like solutions, and hybridization amplitude tuning allows selection of the unoccupied X-point f-hole character. Also theoretically enabled is prediction of a distinct ARPES-measured 3D bulk f-hole-like dispersion at the “H”-point between adjacent X-point d-electron pockets. The H-point f-dispersion then naturally leads to exploration of the Landau level sharp DOS-discontinuity model [4] to quantitatively explain the size and shape of the dominant dHvA orbits.
[1] Li, Science 346, 1208 (2014). [2] Tan, Science 349, 6245 (2015). [3] Sundermann, PRL 120, 016402 (2018). [4] Knolle and Cooper, PRL 115, 146401 (2015).