Ultrafast Atomic Diffusion Inducing a Reversible (2 root 3x2 root 3)R30 degrees <-> (root 3x root 3)R30 degrees Transition on Sn/Si(111) : B

Waked Srour (1, 2) , Daniel G. Trabada (3) , José Ignacio Martinez (3) , Fernando Flores (3) , José Ortega (3) , Manuel Abuín (4) , Yannick Fagot-Révurat (1) , Bertrand Kierren (1) , Amina Taleb-Ibrahimi (2) , Daniel Malterre (1) , Antonio Tejeda (2, 5)

1 IJL - Institut Jean Lamour
2 SSOLEIL - Synchrotron SOLEIL
3 DFTMC - Departamento de Física Teórica de la Materia Condensada [Madrid]
4 UCM - Universidad Complutense de Madrid = Complutense University of Madrid [Madrid]
5 LPS - Laboratoire de Physique des Solides

Dynamical phase transitions are a challenge to identify experimentally and describe theoretically. Here, we study a new reconstruction of Sn on silicon and observe a reversible transition where the surface unit cell divides its area by a factor of 4 at 250 degrees C. This phase transition is explained by the 24-fold degeneracy of the ground state and a novel diffusive mechanism, where four Sn atoms arranged in a snakelike cluster wiggle at the surface exploring collectively the different quantum mechanical ground states.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Waked Srour, Daniel G. Trabada, José Ignacio Martinez, Fernando Flores, José Ortega, et al.. Ultrafast Atomic Diffusion Inducing a Reversible (2 root 3x2 root 3)R30 degrees <-> (root 3x root 3)R30 degrees Transition on Sn/Si(111) : B. Physical Review Letters, 2015, 114 (19), pp.196101. ⟨10.1103/PhysRevLett.114.196101⟩. ⟨hal-01271640⟩