Pressure-induced intermetallic valence transition in BiNiO3
Pressure-induced intermetallic valence transition in BiNiO3
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DOI：
10.1021/ja074880u
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发表时间：
2007-11-21
影响因子：
15
通讯作者：
Attfield, J. Paul
中科院分区：
文献类型：
--
作者：
Azuma, Masaki;Carlsson, Sandra;Attfield, J. Paul
用粉末中子衍射和电子能态计算研究了BiNiO_3钙钛矿在压力作用下的价态变化。在环境压力下，BiNiO3具有不寻常的电荷分布Bi0.53 + Bi0.55 + Ni2 + O3，在高度扭曲的钙钛矿结构的A位点上具有Bi3+和Bi5+电荷的有序性。高压中子衍射测量和键价和计算表明，压力引起的熔融的电荷的反离子化状态导致同时从Ni到Bi的电荷转移，使高压相是金属Bi 3 + Ni 3 + O3。这种前所未有的电荷转移之间的A和B网站的阳离子耦合到电子不稳定性，在两个网站导致各种基态，它是预测，镍-电荷practionated状态也应该是可观察到的。
The valence state change of BiNiO3 perovskite under pressure has been investigated by a powder neutron diffraction study and electron ic-state calculations. At ambient pressure, BiNiO3 has the unusual charge distribution Bi0.53+Bi0.55+Ni2+O3 with ordering of Bi3+ and Bi5+ charges on the A sites of a highly distorted perovskite structure. High-pressure neutron diffraction measurements and bond valence sum calculations show that the pressure-induced melting of the charge disproportionated state leads to a simultaneous charge transfer from Ni to Bi, so that the high-pressure phase is metallic Bi3+Ni3+O3. This unprecedented charge transfer between A and B site cations coupled to electronic instabilities at both sites leads to a variety of ground states, and it is predicted that a Ni-charge disproportionated state should also be observable.