Strain-Induced Segmentation of Magnesian Calcite Thin Films Growing on a Calcite Substrate

Abstract

In crystal growth of mineral species or different compositional members of a solid solution on one another, the degree of lattice mismatch at their interface affects the growth pattern of the precipitating mineral phase. Fast layer-by-layer growth of magnesian calcite on pure calcite (1014) substrates has been observed at Mg 2þ /Ca 2þ ratios of 2-7 using in situ atomic force microscopy. Under solution conditions of calcite saturation states starting from Ω ≈ 33, depending on Mg 2þ /Ca 2þ ratios and carbonate content, bulging in the epitaxial magnesian calcite thin film led to the formation of networks of ridges along the [441], [481], and [421] directions. Eventually, spreading of monolayers stopped at the ridges and formed stationary multilayer steps, resulting in separate and individually growing crystal segments. Molecular dynamics computational modeling suggests that relaxation of strain energy, caused by the interfacial lattice mismatch between pure calcite and the isostructural magnesiumcontaining phase with smaller lattice constants, leads to a semicoherent interface and disordered linear zones cutting through the thin film. As a consequence, the surface bulges up in a way similar to our laboratory observations. This strain-induced segmentation produces aggregates of aligned microcrystals and increase knowledge of the behavior of strained thin films in general.

Epitaxial Growth of Calcite Crystals on Dolomite and Kutnahorite (104) Surfaces

“…Our results show that the growth is mainly controlled by the misfits between the overgrowth and substrate surface lattices. The relatively high lattice misfits (higher than 2.2%) determine a Volmer-Weber epitaxial growth mode, in agreement with previous AFM investigations on epitaxial growth on the surfaces of trigonal carbonates 5,10,14 and sulphates with the barite structure [25][26][27][28] .…”

“…In addition, an estimate of the surface energy from dissolution at different saturation states showed that the monolayers on dolomite have an excess of interfacial strain energy 9 . Similar experiments to those conducted by Higgins and Hu 9 but using calcite (104) faces as substrates, resulted in a more complex growth behaviour [11][12][13][14] . At moderate supersaturated solutions with respect to both dolomite and Mg-calcites, and low magnesium contents, continuous layer-by-layer growth mechanism was reported.…”

“…Since that calcite/dolomite and calcite/kutnahorite misfits are all negative, the formation of screw dislocations on calcite overgrowths can be considered as a response to compressive stress. Sethmann et al 14 …”

Evolution of calcite growth morphology in the presence of magnesium: Implications for the dolomite problem

“…1996]. This hypothesis was later supported by in situ atomic force microscopy (AFM) data [Davis, K. J., Dove, P. M. et al 2000;Davis, K. J., Dove, P. M. et al 2004;Wasylenki, L. E., Dove, P. M. et al 2005;Stephenson, A. E., DeYoreo, J. J. et al 2008;Astilleros, J. M., Fernandez-Diaz, L. et al 2010;Sethmann, I., Wang, J. W. et al 2010;King, H. E., Satoh, H. et al 2013] which showed that Mg incorporation at calcite growth steps is indeed crystallographic direction specific. It was further suggested that the preferential incorporation of Mg in acute steps hinders the growth kinetic and weakens the surface energetic control on step orientations, and ultimately leads to the rounding of growth steps [Falini, G., Gazzano, M. et al 1994;Zhang, Y. P. and Dawe, R. A.…”

The Growth of Gypsum in the Presence of Hexavalent Chromium: A Multiscale Study

“…There are numerous examples of crystal surfaces undergoing changes of nanotopographic features during growth from aqueous solutions containing foreign ions [1][2][3][4][5][6][7]. One of the most remarkable phenomena is the so-called "template effect", which was first defined by Astilleros [8] to describe the reproduction of the original nanotopography of a crystal surface, including etch-pits and step edges, after successive completion of advancing monolayers.…”