Ab initio study of atomic disorder on as-rich GaAs(111)A surface

0449083 - FZÚ 2016 RIV NL eng J - Journal Article
Romanyuk, Olexandr - Mutombo, Pingo - Grosse, F.
Ab initio study of atomic disorder on as-rich GaAs(111)A surface.
Surface Science. Roč. 641, Nov (2015), s. 330-335. ISSN 0039-6028. E-ISSN 1879-2758
R&D Projects: GA ČR GPP204/10/P028
Grant - others:AVČR(CZ) M100101201
Institutional support: RVO:68378271
Keywords : GaAs(111) * surface reconstructions * surface kinetics * density functional theory
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 1.931, year: 2015

Mechanisms for the appearance of disorder on the As-rich GaAs(111)A surface were investigated employing density functional theory (DFT). Focus was given to the As trimer interactions by considering different surface symmetries and rest site occupations. The (2 × 2) and the c(4 × 2) structure models with As trimer and an As rest site were found the most energetically stable under the As-rich experimental conditions at T = 0 K. Low interactions between neighbouring As trimers causes disorder in thermodynamic equilibrium at finite temperatures. A careful analysis of the configurational entropy contributions including the different statistics was carried out. The experimentally observed As-rich (2 × 2) structure was confirmed to be kinetically stabilized. The stabilization mechanism is discussed with respect to the As trimer migration on the surface, which is limited by a large diffusion barrier through the As rest sites.
Permanent Link: http://hdl.handle.net/11104/0250670