fig4

Figure 4. The empty-states STM images are reported in (A) and (B). (A) raw data STM image at a sample bias of +1.7 V and tunneling current I = 500 pA (14.3 × 14.0) nm² from ~0.27 ML of Si deposited at ~220 °C on Si(111)√3 × √3-Bi β-phase; (B) slight FFT filtering of (A) using broad band pass filter. The Si islands and Bi/Si(111) in (B) are labeled, as well as the main crystallographic directions $$ [\bar{2}11] $$, $$ [\bar{1}2\bar{1}] $$ and $$ [\bar{1}\bar{1}2] $$ of Si and the Bi/Si(111) interface, indicated by continuous lines, and including the √3 × √3 surface reconstructions. STM: Scanning tunneling microscopy; ML: monolayer; FFT: fast Fourier transform.