论文标题
确定金属玻璃的三维原子结构
Determining the three-dimensional atomic structure of a metallic glass
论文作者
论文摘要
在我们的日常生活中,诸如玻璃之类的无定形固体无处不在,并且发现广泛的应用,从窗玻璃和太阳能电池到电信和变压器核心。然而,由于缺乏远距离顺序,到目前为止,无定形固体的三维原子结构(3D)原子结构在没有模型拟合的情况下违反了任何直接的实验测定。在这里,我们将多组分金属玻璃作为原理证明,我们先推进原子电子断层扫描,以首次确定无定形固体中的3D原子位置。我们定量地表征了3D原子布置的短距离顺序(SRO)和中距离(MRO)。我们发现,尽管SRO的3D原子堆积是几何无序的,但有些SRO相互连接以形成类似晶体的网络并引起MRO。我们识别四个类似晶体的MRO网络 - 以面部为中心的立方,六角形的封闭式,以身体为中心的立方体和简单的立方 - 在样品中共存,它们显示了转化,但没有方向的顺序。这些观察结果证实,样品某些部分中的3D原子结构与有效的群集堆积模型一致。展望未来,我们预计该实验将为确定各种无定形固体的3D原子坐标打开大门,其对非晶体固体的影响可能与一个世纪前通过X射线晶体学求解的第一个3D晶体结构相媲美。
Amorphous solids such as glass are ubiquitous in our daily life and have found broad applications ranging from window glass and solar cells to telecommunications and transformer cores. However, due to the lack of long-range order, the three-dimensional (3D) atomic structure of amorphous solids have thus far defied any direct experimental determination without model fitting. Here, using a multi-component metallic glass as a proof-of-principle, we advance atomic electron tomography to determine the 3D atomic positions in an amorphous solid for the first time. We quantitatively characterize the short-range order (SRO) and medium-range order (MRO) of the 3D atomic arrangement. We find that although the 3D atomic packing of the SRO is geometrically disordered, some SRO connect with each other to form crystal-like networks and give rise to MRO. We identify four crystal-like MRO networks - face-centred cubic, hexagonal close-packed, body-centered cubic and simple cubic - coexisting in the sample, which show translational but no orientational order. These observations confirm that the 3D atomic structure in some parts of the sample is consistent with the efficient cluster packing model. Looking forward, we anticipate this experiment will open the door to determining the 3D atomic coordinates of various amorphous solids, whose impact on non-crystalline solids may be comparable to the first 3D crystal structure solved by x-ray crystallography over a century ago.