Electronic texture of the thermoelectric oxide Na0.75CoO2

被引：44

作者：

Julien, M. -H. ^{[1
,2
]}

de Vaulx, C. ^{[1
,2
]}

Mayaffre, H. ^{[1
,2
]}

Berthier, C. ^{[1
,2
,3
]}

Horvatic, M. ^{[3
]}

Simonet, V. ^{[4
]}

Wooldridge, J. ^{[5
]}

Balakrishnan, G. ^{[5
]}

Lees, M. R. ^{[5
]}

Chen, D. P. ^{[6
]}

Lin, C. T. ^{[6
]}

Lejay, P. ^{[4
]}

机构：

[1] CNRS, UMR 5588, Spectrometrie Phys Lab, F-38402 St Martin Dheres, France

[2] Univ J Fourier Grenoble, F-38402 St Martin Dheres, France

[3] CNRS, Grenoble High Magnet Field Lab, F-38042 Grenoble, France

[4] UJF, CNRS, Inst Neel, F-38042 Grenoble, France

[5] Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England

[6] Max Planck Inst Solid State Res, D-70569 Stuttgart, Germany

来源：

PHYSICAL REVIEW LETTERS | 2008年 / 100卷 / 09期

基金：

英国工程与自然科学研究理事会;

关键词：

D O I：

10.1103/PhysRevLett.100.096405

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

From Co-59 and Na-23 NMR, we demonstrate the impact of the Na+ vacancy ordering on the cobalt electronic states in Na0.75CoO2: at long time scales, there is neither a disproportionation into 75% Co3+ and 25% Co4+ states, nor a mixed-valence metal with a uniform Co3.25+ state. Instead, the system adopts an intermediate configuration in which 30% of the lattice sites form an ordered pattern of localized Co3+ states. Above 180 K, an anomalous mobility of specific Na+ sites is found to coexist with this electronic texture, suggesting that the formation of the latter may contribute to stabilizing the Na+ ordering. Control of the ion doping in these materials thus appears to be crucial for fine-tuning of their thermoelectric properties.

引用

页数：4

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