Orbital selectivity in Sn adatom adlayer on a Si(111) surface

Unconventional quantum many-particle phenomena naturally emerges when approaching the Mott-Hubbard insulating state. Finding insulator-metal transition in correlated adatoms in semiconductor surfaces provide an ideal material platform to design electronic states which may host superconductivity in two-dimensional electron systems. To uncover the micro-scopics underlying by multi-orbital interactions, we perform density functional plus dynamical mean-field theory calculations for the all-electron 5p-band Hubbard model, unraveling a Mott assisted Kondo insulating state in the atomic Sn layer deposited onto a Si(111) surface, also referred to as α-Sn. We propose that α-Sn is an ideal testing ground to explore hidden orbital selectivity and pseudogap behavior all arising from Mottness and discuss the relevance of our results for pure and hole doped α-Sn in the context of spectroscopy and tunnelling experiments of adatom lattices.