Scattering region of S–Au–S junction. A single Au atom connects to two Au nanowires with S atoms. Blue balls represent Au atoms and two yellow balls represent anchor S atoms. The distances between S atom and center Au atom are (a) 2.5 Å and (b) 4.2 Å respectively. From panel (a) to panel (b), with the increase of distance, the chemical bond between S atom and Au atom breaks. Note that the nanowires extend to each side infinitely.