Al掺杂对Ca_2Co_2O_5结构、电子性质与磁性质的影响研究

采用密度泛函理论模拟分析的方法在赝势法平面波电子波函数的基础上研究了掺杂Ca_2Co_2O_5基体系复合氧化物的微细电子状态,并分析了其晶体结构、能带结构、亚层间及亚层内相互作用及跃迁过程的变化.结果表明,CaCoO层Al掺杂之后晶格a轴和b轴略有收缩,而c轴保持不变,且引起相对能量升高,稳定性较纯Ca_2Co_2O_5有所降低.两种Ca_2Co_2O_5基复合氧化物材料均为金属型能带.掺杂引起d电子对Ca_2Co_2O_5材料电性能的影响弱化,而p电子的影响得到强化.经过Al掺杂之后CoO层在电性能中发挥的作用增大,CaCoO层发挥的作用减小,CoO层中的Co和O对电性能的影响大幅度增强.

Effects of Al Doping on Structural, Electronic and Magnetic Properties of Ca2Co2O5

The detailed electronic states of the doped Ca2Co2O5 compound oxides have been investigated via the framework of density functional theory calculational method through plane wave electron functions and pseudo-potentials. The cell structures, band structure, interactions between the sub-layers and within the sub-layers as well as the modulations of carrier transport are analyzed thereafter. The results indicated that a and b axes are decreased, whereas c axis remains unchanged. The total energy is increased by Al doping and the relative stability is deteriorated. The two oxide materials show metallic band structures. The d state electrons contribute less, but the p state electrons contribute more, to the electrical property after Al doping. The CoO layer plays more important role for the Al doped Ca2Co2O5 in comparison with the intrinsic Ca2Co2O5. The Co and O within the CoO layer contribute much more to the electrical property after Al doping.