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MM: Fachverband Metall- und Materialphysik

MM 22: Functional Materials I

MM 22.4: Vortrag

Dienstag, 27. März 2012, 11:00–11:15, H 1029

Dynamic stabilisation of polar oxide growth: the case of MgO(111) — •Philip Hasnip and Vlado Lazarov — University of York, York, UK

Intrinsic polar materials such as metal-oxides are some of the most commonly used materials in electronic, magnetic and chemical applications. Along the polar direction, these materials consist of oppositely charged ionic planes and this polarity dominates the growth process. Attempts to grow polar oxides in their polar direction often result in surface faceting, surface reconstructions, adatoms or surface metallisation as the system attempts to heal the polarity and prevent a divergent electrostatic dipole.

By using MgO(111) as a model system for polar oxide film growth, we show by ab initio calculations that H can act as a surfactant, stabilising the growth dynamically without disrupting the growth or becoming trapped in the film. The continuous presence of H during the growth of a MgO(111) film efficiently removes the microscopic dipole moment, thus enabling the growth of perfect fcc-ordered MgO(111) films. These theoretical predictions are confirmed experimentally by molecular beam epitaxy single crystal growth of MgO(111) on SiC(0001).