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Polarity compensation mechanisms on the perovskite surface KTaO3(001)

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Science  02 Feb 2018:
Vol. 359, Issue 6375, pp. 572-575
DOI: 10.1126/science.aar2287

Compensating a polar surface

An ionic crystal surface can be electrostatically unstable, and the surface must reconstruct in some way to avoid this “polar catastrophe.” Setvin et al. used scanning probe microscopies and density functional theory to study the changes in the polar surface of the perovskite KTaO3. They observed several structural reconstructions as the surface cleaved in vacuum was heated to higher temperatures. These ranged from surface distortions to the formation of oxygen vacancies to the development of KO and TaO2 stripes. Hydroxylation after exposure to water vapor also stabilized the surface.

Science, this issue p. 572