Low-Temperature Structure of the Quarter-Filled Ladder Compound α'-NaV2O5
Low-Temperature Structure of the Quarter-Filled Ladder Compound α'-NaV2O5
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DOI：
10.1143/jpsj.71.385
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发表时间：
2001-09
影响因子：
1.7
通讯作者：
H. Sawa;E. Ninomiya;T. Ohama;H. Nakao;K. Ohwada;Y. Murakami;Y. Fujii;Y. Noda;M. Isobe;Y. Ueda
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文献类型：
--
作者：
H. Sawa;E. Ninomiya;T. Ohama;H. Nakao;K. Ohwada;Y. Murakami;Y. Fujii;Y. Noda;M. Isobe;Y. Ueda
用同步辐射X射线衍射法测定了γ '-NaV 2 O 5的低温超结构。低于与原子位移和电荷有序在34 K的相变温度，我们观察到布拉格峰分裂，这提供了证据，LT结构是单斜的。确定了LT的结构为（a - B）×2 B ×4 c，空间群为A112，其中a，B和c代表高温斜方晶系晶胞。用键价和法估算了V离子的价态，结果表明，V位明显地分为V4+和V5+两组，电荷有序模式为zigzag。这种LT结构与共振X射线和NMR测量结果一致，并且与先前报道的LT结构形成鲜明对比，该结构包括V 4.5+位点。
The low-temperature (LT) superstructure of α'-NaV 2 O 5 was determined by synchrotron radiation X-ray diffraction. Below the phase transition temperature associated with atomic displacement and charge ordering at 34 K, we observed Bragg peak splittings, which provide evidence that the LT structure is monoclinic. It was determined that the LT structure is ( a - b )×2 b ×4 c with the space group A 112, where a , b and c represent the high-temperature orthorhombic unit cell. The valence estimation of V ions according to the bond valence sum method shows that the V sites are clearly separated into two groups of V 4+ and V 5+ with a z i g z a g charge-ordering pattern. This LT structure is consistent with resonant X-ray and NMR measurements, and is in striking contrast to the LT structure previously reported, which includes V 4.5+ sites.