Fig. 1: Local-density of state maps through the valence-band edge of the Sn/Si monolayer.

a Topographic map of the tin monolayer deposited on silicon. For both topography and spectroscopic data, the bias voltage is -1V and the current setpoint 100 pA. Except is specified otherwise, the temperature is fixed at 300 mK throughout the paper. b dI/dV spectra taken at the lower band-edge of the tin monolayer along a vertical line (cf. the black arrow indicates the X position on a). The color bar codes for the dI/dV values. c Crystalline structure of the tin \(\sqrt{3}\times \sqrt{3}\) tin reconstruction on a Si(111) surface. d dI/dV spectroscopy at 4K reveals a large gap of roughly 0.6 eV. e dI/dV map at −0.48 eV, very close to the band-edge. The color bar codes for the differential conductance at a given energy and position in pS. f dI/dV maps at fixed energy at E = {−0.65, −0.6, −0.55, −0.5} eV along with their Fourier transform (quasi-particle interference patterns). The Relative Standard Deviation (RSD) of the dI/dV map is given on each panel, and the color bar codes for the differential conductance dI/dV.