BCN-M: A Free Computational Tool for Generating Wulff-like Nanoparticle Models with Controlled Stoichiometry

A thorough knowledge of the atomic structure of nanomaterials
is
of high importance to understand their properties. This requires developing
nanoparticle models, which is not always straightforward, particularly
in the case of nonpure metallic systems. The bulk cut nanoparticle
model (BCN-M) computational tool generates Wulff-like models for binary
materials with controlled stoichiometry automatically with none or
little need for further manipulation from the user. The models are
obtained exclusively by introducing the structure of the bulk material,
its symmetry, the surface energies of the most representative surfaces,
and information about surface termination as input data. The algorithm
produces different structural model sets, and the quality of these
models is evaluated using different criteria: (i) the deviation from
an ideal Wulff shape, (ii) the global coordination of surface metal
atoms, and (iii) the polarity of the model. BCN-M has been applied
to 15 different materials, leading to a variety of models that cover
the most relevant binary ionic structures and symmetries (cubic, tetragonal,
hexagonal, and monoclinic). The resulting models can be used for structure
analysis of ideal systems as well as their simulation. BCN-M is available
as a free web platform (https://bcnm.qf.uab.cat) or as a downloadable utility, and it is expected to be an important
tool for the design of future nanomaterials.

深入了解纳米材料的原子结构，对于理解其性能具有至关重要的意义。而要达成这一目标，需要构建纳米粒子模型，但这一过程往往并非易事，对于非纯金属体系而言更是如此。体相切割纳米粒子模型（bulk cut nanoparticle model, BCN-M）计算工具可自动为具备可控化学计量比的二元材料生成类沃尔夫（Wulff）结构模型，且几乎无需用户进行额外调整。该模型仅需以体相材料的晶体结构、对称性、最具代表性晶面的表面能以及表面终止态信息作为输入数据即可生成。该工具的算法可生成多组不同的结构模型，并通过以下三项标准对模型质量进行评估：(i) 与理想沃尔夫结构的偏差程度；(ii) 表面金属原子的整体配位数；(iii) 模型的极性。BCN-M已在15种不同材料上完成应用测试，生成的各类模型覆盖了最具代表性的二元离子晶体结构与晶系（立方、四方、六方及单斜晶系）。所生成的模型既可用于理想体系的结构分析，也可用于相关模拟研究。BCN-M可通过免费在线平台（https://bcnm.qf.uab.cat）或可下载工具包获取，有望成为未来纳米材料设计领域的重要工具。