Valence and spin fluctuations in the Mn-doped ferroelectric BaTiO3
Valence and spin fluctuations in the Mn-doped ferroelectric BaTiO3
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DOI：
10.1103/physrevb.98.075155
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发表时间：
2018-03
影响因子：
3.7
通讯作者：
S. Mandal;R. Cohen;K. Haule
中科院分区：
文献类型：
--
作者：
S. Mandal;R. Cohen;K. Haule
采用密度泛函理论（DFT）结合动态平均场理论（DMFT）研究了Mn在BaTiO_{3}$中的替代效应.我们发现了强烈的电荷和自旋波动。在没有补偿氧空位的情况下，基态被发现是两个不同原子价态$3{d}^{4}$和$3{d}^{5}$的量子叠加。在相邻位置引入补偿氧空位减少了由于从Mn到其配体的电子跳跃的减少而引起的电荷和自旋波动。结果，原子价的涨落减少，原子价被紧密地固定在高自旋$3{d}^{5}$态。在这里，我们表明，包括电荷和自旋的波动是必要的，以获得一个准确的过渡金属掺杂的铁电基态。
We study Mn substitution for Ti in ${\mathrm{BaTiO}}_{3}$ with and without compensating oxygen vacancies using density functional theory (DFT) in combination with dynamical mean-field theory (DMFT). We find strong charge and spin fluctuations. Without compensating oxygen vacancies, the ground state is found to be a quantum superposition of two distinct atomic valences, $3{d}^{4}$ and $3{d}^{5}$. Introducing a compensating oxygen vacancy at a neighboring site reduces both charge and spin fluctuations due to the reduction of electron hopping from Mn to its ligands. As a consequence, valence fluctuations are reduced, and the valence is closely fixed to the high spin $3{d}^{5}$ state. Here we show that inclusion of charge and spin fluctuations is necessary to obtain an accurate ground state of transition metal-doped ferroelectrics.