奥地利应用物理研究所Jan Balajka研究团队报道了Al₂O₃(0001)表面的化学计量重建。相关研究成果发表在2024年9月13日出版的《科学》。

材料的宏观性能源于根本的原子尺度细节，但对于绝缘体来说，解析表面结构仍然是一个挑战。

该文中，研究人员使用具有原子定义尖端的非接触式原子力显微镜对α-氧化铝（α-Al₂O₃）的基底（0001）平面进行了成像。表面形成了一个复杂的（√31×√31）R±9°重建。

单个氧和铝表面原子的横向位置直接来自实验，研究人员通过计算建模确定了这些如何连接到下面的晶体块。在重组之前，表面Al原子呈现不利的三重平面配位；重建能够与次表面O再混合，从而获得可观的能量增益。重建的表面保持Al₂O₃化学计量比。

附：英文原文

Title: Stoichiometric reconstruction of the Al2O3(0001) surface

Author: Johanna I. Hütner, Andrea Conti, David Kugler, Florian Mittendorfer, Georg Kresse, Michael Schmid, Ulrike Diebold, Jan Balajka

Issue&Volume: 2024-09-13

Abstract: Macroscopic properties of materials stem from fundamental atomic-scale details, yet for insulators, resolving surface structures remains a challenge. We imaged the basal (0001) plane of α–aluminum oxide (α-Al2O3) using noncontact atomic force microscopy with an atomically defined tip apex. The surface formed a complex (√31 × √31)R±9° reconstruction. The lateral positions of the individual oxygen and aluminum surface atoms come directly from experiment; we determined with computational modeling how these connect to the underlying crystal bulk. Before the restructuring, the surface Al atoms assume an unfavorable, threefold planar coordination; the reconstruction allows a rehybridization with subsurface O that leads to a substantial energy gain. The reconstructed surface remains stoichiometric, Al2O3.

DOI: adq4744

Source: https://www.science.org/doi/10.1126/science.adq4744