First Principles Calculation of Defect Formation Energies in Sr- and Mg-Doped LaGaO3
First Principles Calculation of Defect Formation Energies in Sr- and Mg-Doped LaGaO3
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DOI：
10.1021/jp049808m
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发表时间：
2004-05
影响因子：
3.3
通讯作者：
A. Kuwabara;I. Tanaka
中科院分区：
文献类型：
--
作者：
A. Kuwabara;I. Tanaka
用投影增广波方法对掺锶和/或掺镁的三方相LaGaO_3进行了第一性原理计算。在考虑温度和氧分压的情况下，系统地计算了10种缺陷的形成能。Sr2+离子在La位稳定，而在Ga位稳定，而Mg2+离子在Ga位稳定。当温度为500−~1600K，氧分压为10~(-21)~1atm时，伴随氧空位形成的掺杂溶液的能量最低。在这些条件下，导致n型或p型导电性的缺陷在能量上是不利的。本文的理论结果与文献中有关掺杂LaGaO_3晶位择优和离子电导率与氧分压关系的实验结果是一致的。在500−和1600K温度下，用O2-空位的形成取代Sr2+和Mg2+离子是主要的缺陷.
First-principles calculations with projector augmented wave method has been carried out for Sr- and/or Mg-doped rhombohedral LaGaO3. The formation energies of 10 kinds of defects have been systematically computed in consideration of temperature and oxygen partial pressure. Sr2+ ion is found to be stable at La site rather than Ga site, whereas Mg2+ ion is stable at Ga site. The solution of dopants accompanied with the formation of oxygen vacancies shows the lowest energy at temperatures of 500−1600 K and oxygen partial pressure of 10-21 to 1 atm. Defects resulting in n- or p-type conductivity are energetically unfavorable under these conditions. The present theoretical results are consistent with experimental results of doped LaGaO3 in the literature regarding both site preference of dopants and the dependence of ionic conductivity on oxygen partial pressure. Substituting Sr2+ and Mg2+ ions with the formation of O2- vacancies are confirmed to be predominant defects in temperatures of 500−1600 K and oxygen ...