Dresden 2014 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 9: Poster Session DF
DF 9.2: Poster
Dienstag, 1. April 2014, 18:30–20:00, P1
Lithium Niobate (0001) Surfaces in Thermodynamic Equilib- rium with Ambient Conditions — •Rebecca Hölscher, Simone Sanna, and Wolf Gero Schmidt — University of Paderborn
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, the (0001) surface reactivity can be manipulated by polarization reversal. This opens the possibility for the realization of devices such as molecular detectors1.
In contrast to the popularity of the material, few is known about the microscopic structure of the (0001) surfaces. Recently the surface structure in liquid solution has been demonstrated by a joint AFM and DFT investigation2. At relatively dry conditions only the value for the surface charge is available3.
As a further step towards the simulation of realistic surfaces, the adsorption of the most important components of dry air (N2, O2, CO2, CH4, H2, N2O, CO) is simulated and the adsorption energies and geometries are determined. We present phase diagrams in dependence of temperature and pressure for every component and in presence of different amounts of water. From these phase diagrams we can extract the desorption temperatures. Additionally the influence of the adsorbed molecules on the surface charge is estimated.
[1] D. Li, M. H. Zhao, et al., Nat. Mat. 7, 473 (2008)
[2] S. Rode, R. Hölscher, et al., Phys. Rev. B 86, 075568 (2012)
[3] F. Johann and E. Soergel, Apl. Phys. Let. 95, 232906 (2009)