Topological superconductivity in Sn/Si(111) driven by nonlocal Coulomb interactions

Few-monolayer Ga film on Si(111): illusive gallenene formation and localization instead of superconductivity

“…This can be tested experimentally by growing similar films on the various substrates. For example, it has been shown that changing a bare Si(111) surface for the Si(111) ffiffiffi 3 p × ffiffiffi 3 p -B reconstruction alters the properties of the Sn submonolayer from those of a Mott insulator 9 to superconducting with T c ∼ 4.7 ± 0.3 K, [10][11][12] but does not greatly affect the superconducting properties of the two-atom-thick In film. 13 Introducing a gold interlayer promoted the superconductive properties of Pb layers on Si(100).…”

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

“…Adsorption of group-IV elements on semiconductor surfaces such as Si, Ge or SiC [20][21][22] often promotes intriguing charge and spin phases at the two-dimensional (2D) limit, including unconventional [23,24] and possibly topological superconductivity [25], charge density wave [26,27] and unusual magnetism [28][29][30]. Interestingly, adsorption of one third monolayer Sn on Ge(111) or Si(111) surface leads to the formation of an atomic Sn 2D- layer (see fig.…”

“…[23], this singularity originates from the flat saddle-point dispersion near the M -point in the surface state band dispersion, suggesting the possibility of a phonon-mediated superconductivity due to an interfacial coupling with the Si substrate. However, the strong electronic reconstruction arising from local [20,28,29,32] and non-local [25,27] electron-electron interactions in the Sn 2D layer might suppress the phonon-driven s-wave mechanism [23]. In reality, geometrical frustration of the triangular lattice and strong correlations might induce a chiral superconducting order parameter [13,24] giving rise to non-trivial topological superconductivity [35,39].…”