【摘要】 采用第一性原理密度泛函理论模拟U在Gd₂Zr₂O₇烧绿石中的固溶,在低浓度U掺杂时,Gd₂Zr₂O₇烧绿石保持烧绿石结构;随着U掺杂浓度增加,Gd₂(Zr_2-yU_y)O₇和(Gd_2-yU_y)Zr₂O₇体系的晶格常数发生线性变化.计算结果表明,由于总能较低,U原子更偏向于替代无序换位后Gd₂Zr₂O₇晶格中B位的Gd原子.更多还原

【Abstract】 Ab initio calculation is performed to investigate the uranium solubility in different sites of Gd₂Zr₂O₇ pyrochlore.TheGd₂Zr₂O₇ maintains its pyrochlore structure at low uranium dopant levels,and the lattice constants of Gd₂(Zr_2-yU_y)O₇ and(Gd_2-yU_y)Zr₂O₇ are generally expressed as being linearly related to the uranium content y.Uranium is found to be a preferable substitute for the B-site gadolinium atoms in cation-disordered Gd₂Zr₂O₇（where gadolinium and zirconium atoms are swapped） over the A-site gadolinium atoms in ordered Gd₂Zr₂O₇ due to the lower total energy of(Gd_2-yZr_y)(Zr_2-yU_y)O₇.更多还原