Electronic properties of normal and extended Hubbard model for bilayer cuprates

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

“…A characteristic one-particle feature in the 2D electronic structure of α-Sn is the presence of a narrow band with mostly Sn-5p z orbital character which crosses E F and is well-separated from other bonding and anti-bonding bands emerging at high energies [32]. Apart from the narrow bandwidth (W ≈ 0.4 eV) [32] an additional interesting feature of the effective surface band in the semiconducting gap of α-Sn is the existence of a van Hove singularity located near 30 meV below E F , suggesting an extended van Hove singularity scenario in α-Sn similar to that reported, for example, for doped graphene [36], Sr 2 RuO 4 [37], bilayer cuprates [38] as well as to Moiré materials near the van Hove filling [39]. Interestingly, upon hole doping the insulating parent compound [13,14,22,28,40] via modulation-doped Si surface [14,22,23], extant tunneling spectroscopy data reveal a sharp spike situated 6.0 meV below E F followed by a coherent quasiparticle peak [13,23,34], located slightly above E F in experiment.…”