Dynamical Study of Single Silver Atoms on Si(111)-7 ×7 Surfaces

Abstract

The dynamics and interactions of silver atoms on Si(111)-7 ×7 surfaces are investigated using variable-temperature scanning tunneling microscopy (STM). The activation energies and pre-exponential factors upon the room temperature are estimated to be 0.81 and 0.9 eV, and 109.65 and 1010.68 for the hopping out of the faulted halves and for hopping out of unfaulted halves, respectively. The behavior exhibited by two silver atoms that jump into a single half-unit cell is also addressed. Details of the tracking of single silver atoms that hop within a 7 ×7 half-unit cell are reexamined at ∼80 K using low-temperature STM. The analytical data revealed that silver atoms diffuse within a 7 ×7 unit cells via a corner adatom–rest atom–center adatom–rest atom–corner adatom diffusion pathway in a faulted half under the stress associated with 7 ×7 reconstruction.