Clear signature of the (2 x 1) reconstruction of calcite (1014).
Clear signature of the (2 x 1) reconstruction of calcite (1014).
复制标题
方解石 (1014) 的 (2 x 1) 重建的清晰特征。
作者：
J. Schütte;P. Rahe;Lutz Tröger;S. Rode;R. Bechstein;M. Reichling;A. Kühnle
方解石是一种非常重要的矿物，在生物矿化、生物分子吸附、反应以及工业和日常生活等研究领域发挥着至关重要的作用。因此，人们利用原子力显微镜等直接成像技术以及光谱和衍射技术对方解石最稳定的解理面进行了广泛的研究。方解石的(1014)解理面有几种不同于简单的整体截断结构的表面结构，文献中关于解理面是否存在(2×1)重构的争论还在继续。我们在超高真空条件下用高分辨率非接触原子力显微镜(NC-AFM)研究了(1014)解理面，得到了(2×1)重构的明显特征。这种重建只能在非常窄的尖端表面距离范围内观察到，这解释了为什么在一些实验中观察到了重建，而在另一些实验中没有观察到重建。此外，由于所有样品的制备都是在超高真空中进行的，因此由吸附诱导的(2×1)重构的可能性似乎相当小。此外，针尖引起的表面变化也被排除为观察到的重建的起源。综上所述，我们的研究表明，(2×1)重构是方解石(1014)解理面的真实表面性质。
Calcite is a mineral of fundamental importance that plays a crucial role in many fields of research such as biomineralization, biomolecule adsorption, and reactivity as well as industrial and daily life applications. Consequently, the most stable cleavage plane of calcite has been studied extensively using both direct imaging techniques such as atomic force microscopy as well as spectroscopic and diffraction techniques. Several surface structures have been reported for the (1014) cleavage plane of calcite differing from the simple bulk-truncated structure and an ongoing controversy exists in literature whether the cleavage plane exhibits a (2 x 1) reconstruction or not. We study the (1014) cleavage plane using high-resolution noncontact atomic force microscopy (NC-AFM) under ultrahigh vacuum conditions and obtain a clear signature of the (2 x 1) reconstruction. This reconstruction is observed in very narrow tip-surface distance ranges only, explaining why in some experiments the reconstruction has been observed and in others not. Moreover, as all sample preparation is performed in ultrahigh vacuum, the possibility of the (2 x 1) reconstruction being adsorbate-induced appears rather unlikely. Additionally, tip-induced surface changes are ruled out as origin for the observed reconstruction either. In conclusion, our study suggests that the (2 x 1) reconstruction is a true surface property of the (1014) cleavage plane of calcite.