Atomically perfect bismuth lines on Si(001)

Atomically perfect bismuth lines form on Si(001) by a selective desorption process around the temperature at which most of the bismuth desorbs from bi smuth epitaxial layers. The lines are perpendicular to the silicon dimer ro ws; they are 1 nm wide and can be hundreds of nm long in a flat Si(001) sur face. They are utterly free of kinks or other defects. In our proposed mode l three silicon dimers in the surface are replaced with two Bi dimers, with a rebonded missing dimer defect between them. It is suggested that the lin es are straight because of kinetic reasons rather than thermodynamic ones - they form straight and are unable subsequently to kink.