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

共 30 条

[11] Large enhancement of the thermopower in NaxCoO2 at high Na doping [J].

Lee, Minhyea ;

Viciu, Liliana ;

Li, Lu ;

Wang, Yayu ;

Foo, M. L. ;

Watauchi, S. ;

Pascal, R. A., Jr. ;

Cava, R. J. ;

Ong, N. P. .

NATURE MATERIALS, 2006, 5 (07) :537-540

[12] Sodium cobaltates: Crystal growth, structure, thermoelectricity, and superconductivity [J].

Lin, C. T. ;

Chen, D. P. ;

Maljuk, A. ;

Lemmens, P. .

JOURNAL OF CRYSTAL GROWTH, 2006, 292 (02) :422-428

[13] Na-induced correlations in NaxCoO2 [J].

Marianetti, C. A. ;

Kotliar, G. .

PHYSICAL REVIEW LETTERS, 2007, 98 (17)

[14] Atomic-scale sources and mechanism of nanoscale electronic disorder in Bi2Sr2CaCu2O8+δ [J].

McElroy, K ;

Lee, J ;

Slezak, JA ;

Lee, DH ;

Eisaki, H ;

Uchida, S ;

Davis, JC .

SCIENCE, 2005, 309 (5737) :1048-1052

[15] Ab initio study of sodium ordering in Na0.75CoO2 and its relation to Co3+/Co4+ charge ordering -: art. no. 172103 [J].

Meng, YS ;

Van der Ven, A ;

Chan, MKY ;

Ceder, G .

PHYSICAL REVIEW B, 2005, 72 (17)

[16] Ferromagnetism, paramagnetism, and a Curie-Weiss metal in an electron-doped Hubbard model on a triangular lattice [J].

Merino, J. ;

Powell, B. J. ;

McKenzie, Ross H. .

PHYSICAL REVIEW B, 2006, 73 (23)

[17] 23Na NMR evidence for charge order and anomalous magnetism in NaxCoO2 -: art. no. 167601 [J].

Mukhamedshin, IR ;

Alloul, H ;

Collin, G ;

Blanchard, N .

PHYSICAL REVIEW LETTERS, 2004, 93 (16) :167601-1

[18] 59Co NMR study of the Co states in superconducting and anhydrous cobaltates -: art. no. 247602 [J].

Mukhamedshin, IR ;

Alloul, H ;

Collin, G ;

Blanchard, N .

PHYSICAL REVIEW LETTERS, 2005, 94 (24)

[19]

MUKHAMEDSHIN IR, ARXIVCONDMAT0703561, P65414

[20] Spin dynamics in the carrier-doped S=1/2 triangular lattice of NaxCoO2•yH2O -: art. no. 237201 [J].

Ning, FL ;

Imai, T ;

Statt, BW ;

Chou, FC .

PHYSICAL REVIEW LETTERS, 2004, 93 (23)

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