First-Principles Study on Electronic Structure and Thermodynamic Stability of Sr(Ti,Ru)O3
First-Principles Study on Electronic Structure and Thermodynamic Stability of Sr(Ti,Ru)O3
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Sr(Ti,Ru)O3电子结构和热力学稳定性的第一性原理研究
DOI：
10.1143/jjap.40.l117
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发表时间：
2001
影响因子：
1.5
通讯作者：
Takashi Kawakubo Takashi Kawakubo
中科院分区：
文献类型：
--
作者：
Tatsuo Shimizu Tatsuo Shimizu;Takashi Kawakubo Takashi Kawakubo
用第一性原理法研究了Sr(Ti,Ru)O3的电子结构和热力学稳定性。对于Ru浓度较小的电子结构，Ru t2g态出现在SrTiO3带隙中间以下。在这种情况下，Ru t2g态的波函数定域在Ru位点。当Ru浓度增加到50 mol%以上时，隙内态逐渐离域。因此，一种导电的Sr(Ti,Ru)O3薄膜有望实现。另一方面，随着Ru浓度的降低，Sr(Ti,Ru)O3薄膜的热力学稳定性相对于SrRuO3薄膜显著增强。Ru浓度大于60 mol%的Sr(Ti,Ru)O3会氧化相邻的（Ti,Al）N层，这是记忆电池电容器中常用的阻挡金属。总之，Ru浓度约为50 mol%的Sr(Ti,Ru)O3是一种很有前途的新型电极候选材料。
Not only the electronic structure but also the thermodynamic stability of Sr(Ti,Ru)O3 is investigated using the first-principles method. For the electronic structure with small Ru concentration, the Ru t2g states appear below the middle of the band gap of SrTiO3. In this case, the wave functions of the Ru t2g states are localized at the Ru site. As a Ru concentration increases to more than 50 mol%, the inside-gap states gradually become delocalized. Therefore, a conductive Sr(Ti,Ru)O3 thin film is expected. On the other hand, thermodynamic stability of a Sr(Ti,Ru)O3 thin film is enhanced drastically relative to that of SrRuO3, as Ru concentration decreases. Sr(Ti,Ru)O3 with Ru concentration of more than 60 mol% may oxidize the neighboring (Ti,Al)N layer, which is often used as a barrier metal in memory-cell capacitors. In short, Sr(Ti,Ru)O3 with Ru concentration of about 50 mol% is proposed as a promising candidate material for new electrodes.