分子束外延合成三元氮化物PrTaN₂及其晶体结构测定
Molecular beam epitaxy synthesis of ternary nitride PrTaN$_2$ and its crystal structure determination
浏览论文内容
中文总结 AI 辅助
该研究通过分子束外延合成新型三元氮化物PrTaN₂，开发基于结构因子的拟合程序完成其晶体结构测定，为探索新型复杂氮化物材料提供了方法途径。
中文摘要 AI 辅助
我们报道了利用分子束外延（molecular beam epitaxy）作为薄膜合成方式的新型三元氮化物PrTaN₂的发现。将用于难熔元素的电子束蒸发技术与射频氮自由基源相结合，可在高氮化环境下实现生长，从而获得块体合成中不易得到的物相。通过X射线衍射和高角环形暗场扫描透射电子显微镜进行的结构表征显示，该化合物结晶为正交晶系结构，在YAlO₃衬底上以明确的取向生长，且基本无应变。为从有限的薄膜衍射数据中确定晶体结构，我们开发了基于结构因子的拟合程序。结合消光规则与Wyckoff位置的约束，拟合参数数量大幅减少，实现了可靠的结构测定。系统排除Pr-Ta-N体系中的替代候选物相，结合结构因子拟合，确定其空间群为P222并得到原子坐标。本研究结果表明，采用分子束外延的薄膜生长可稳定此前未被探索的三元氮化物，并建立了此类体系中结构测定的实用方法，为探索新型复杂氮化物材料提供了途径。
英文摘要
We report the discovery of a novel ternary nitride PrTaN$_2$ synthesized as a thin film using molecular beam epitaxy. The combination of e-beam evaporation for refractory elements and a radio-frequency nitrogen radical source enables growth under a highly nitriding environment, providing access to phases not readily obtained in bulk synthesis. Structural characterization by X-ray diffraction and high-angle annular dark-field scanning transmission electron microscopy reveals that the compound crystallizes in an orthorhombic structure and grows with a well-defined orientation on YAlO$_3$ substrates, while remaining essentially strain-free. To determine the crystal structure from limited thin-film diffraction data, we developed a fitting procedure based on structure factors. By combining extinction rules with constraints from Wyckoff positions, the number of fitting parameters is significantly reduced, enabling reliable structure determination. Systematic exclusion of alternative candidate phases in the Pr-Ta-N system, together with structure factor fitting, identifies the space group as $P222$ and determines the atomic coordinates. The present results demonstrate that thin-film growth with molecular beam epitaxy can stabilize previously unexplored ternary nitrides, and establish a practical approach for structural determination in such systems. This work provides a pathway for the exploration of new complex nitride materials.
