Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 21: Morphology Prediction at Interfaces: Theory meets Experiment

O 21.5: Poster

Monday, March 7, 2016, 18:15–20:30, Poster E

Behaviour of the water lithium niobate interface studied from first principles — •Rebecca Hölscher, Simone Sanna, and Wolf Gero Schmidt — Paderborn University

Lithium niobate (LiNbO₃, LN) is a frequently used material for optical and acoustic applications due to its strong piezoelectric, pyroelectric, and photorefractive properties. As for other ferroelectric materials, manipulating the polarization can change the surface reactivity. This opens the possibility for the realization of molecular detectors and other devices [1]. The water lithium niobate interface is largely unknown. Moreover, recent results show that basic properties of water such as the freezing temperature are strongly polarization dependent [2]. We present here ab initio calculations on the adsorption of water films on both the positive and the negative Z-cut and the X-Cut surface of LN. The adsorption is modelled by means of density functional theory (DFT) within the generalized gradient approximation [3,4]. The interface atomic structure and dynamics are calculated using Molecular Dynamic simulations at room temperature. The influence of the surface polarity on the water layer is investigated by means of a correlation function analysis.

[1] D. Li, et al., Nature Materials 7 (2008) 473.

[2] D. Ehre et al., Science 327 (2010) 672.

[3] W.G. Schmidt, et al., Phys. Rev. B 77 (2008), 035106.

[4] S. Sanna, A.V. Gavrilenko, W.G. Schmidt, Phys. Stat. Sol. C 7 (2010) 145.