Formation of an unconventional Ag valence state in Ag2NiO2
Formation of an unconventional Ag valence state in Ag2NiO2
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Ag2NiO2 中非常规 Ag 价态的形成
DOI：
10.1103/physrevb.75.180404
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发表时间：
2006
影响因子：
3.7
通讯作者：
D. Khomskii
中科院分区：
文献类型：
--
作者：
M. Johannes;S. Streltsov;I. Mazin;D. Khomskii
最近合成的新材料Ag 2NiO 2中的Ag离子采用了极不寻常的1价，使Ni离子为3+，而不是预期的2+。使用第一性原理计算，我们表明，这种神秘的低价态出现由于两个Ag层之间的强键-反键相互作用，驱动较低的带下面的O p复合物，消除了传统的Ag 1+价态的可能性。比热系数的强重整化可能是由于强的自旋涨落，其源于铁磁金属双交换和90°超交换以及反铁磁常规超交换通过Ni-O-Ag-O-Ni路径相互作用的几乎完全补偿。
The Ag ion in the recently synthesized novel material Ag2NiO2 adopts an extremely unusual valency of 1 , leaving the Ni ion as 3+, rather than the expected 2+. Using first-principles calculations, we show that this mysterious subvalent state emerges due to a strong bonding-antibonding interaction between the two Ag layers that drives the lower band beneath the O p complex, eliminating the possibility of a conventional Ag 1+ valence state. The strong renormalization of the specific heat coefficient is likely due to strong spin fluctuations that stem from nearly complete compensation of the ferromagnetic metallic double exchange and 90° superexchange and antiferromagnetic conventional superexchange via Ni-O-Ag-O-Ni path interactions.