info:eu-repo/semantics/article
Manganese 3×3 and √3×√3-R30 â̂̃ structures and structural phase transition on w-GaN(0001̄) studied by scanning tunneling microscopy and first-principles theory
Fecha
2013-04Registro en:
Chinchore, Abhijit V.; Wang, Kangkang; Shi, Meng; Mandru, Andrada; Liu, Yinghao; et al.; Manganese 3×3 and √3×√3-R30 â̂̃ structures and structural phase transition on w-GaN(0001̄) studied by scanning tunneling microscopy and first-principles theory; American Physical Society; Physical Review B: Condensed Matter and Materials Physics; 87; 16; 4-2013; 1654261-16542611
1098-0121
CONICET Digital
CONICET
Autor
Chinchore, Abhijit V.
Wang, Kangkang
Shi, Meng
Mandru, Andrada
Liu, Yinghao
Haider, Muhammad
Smith, Arthur R.
Ferrari, Valeria Paola
Barral, María Andrea
Ordejón, Pablo
Resumen
Manganese deposited on the N-polar face of wurtzite gallium nitride [GaN (0001̄)] results in two unique surface reconstructions, depending on the deposition temperature. At lower temperature (less than 105 â̂̃C), it is found that a metastable 3×3 structure forms. Mild annealing of this Mn 3×3 structure leads to an irreversible phase transition to a different, much more stable √3×√3-R30â̂̃ structure which can withstand high-temperature annealing. Scanning tunneling microscopy (STM) and reflection high-energy electron diffraction data are compared with results from first-principles theoretical calculations. Theory finds a lowest-energy model for the 3×3 structure consisting of Mn trimers bonded to the Ga adlayer atoms but not with N atoms. The lowest-energy model for the more stable √3×√3-R30â̂̃ structure involves Mn atoms substituting for Ga within the Ga adlayer and thus bonding with N atoms. Tersoff-Hamman simulations of the resulting lowest-energy structural models are found to be in very good agreement with the experimental STM images.