Soft X-ray Absorption and Photoemission Spectroscopy Study of Cobalt-Based Thermoelectric Oxides: Ca3Co4O9, Ca3Co2O6, and Bi2Sr2Co2Oy

被引：0

作者：

Kang, J. -S. ^{[1
]}

Lee, H. J. ^{[1
]}

Kim, D. H. ^{[1
]}

Fujii, T. ^{[2
]}

Terasaki, I. ^{[2
]}

Park, H. L. ^{[3
]}

Jeong, Y. H. ^{[3
]}

Min, B. I. ^{[3
]}

机构：

[1] Catholic Univ Korea, Dept Phys, Puchon 420743, South Korea

[2] Waseda Univ, Dept Appl Phys, Tokyo 1698555, Japan

[3] POSTECH, Dept Phys, Pohang 790784, South Korea

来源：

JOURNAL OF ELECTRONIC MATERIALS | 2009年 / 38卷 / 07期

关键词：

XAS; PES; electronic structure; thermopower; cobalt oxides; TRANSITION-METAL COMPOUNDS; MISFIT-LAYERED COBALTITE; SINGLE-CRYSTALS; THERMOPOWER; SYMMETRY; POWER;

D O I：

10.1007/s11664-008-0631-0

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

The electronic structures of Co-based potential thermoelectric (TE) oxides, including Ca3Co4O9 and Bi(2)Sr(2)Co(2)Oy (y = 8 + delta) single crystals and polycrystalline Ca3Co2O6, have been investigated by employing soft x-ray absorption spectroscopy (XAS) and photoemission spectroscopy (PES). Co 2p XAS measurements show that Co ions are nearly trivalent (Co3+) in all of these Co-based TE oxides with a small mixture of Co4+ ions in Bi2Sr2Co2Oy. Valence-band PES and O 1s XAS measurements show that the occupied Co 3d states are located at the top of the valence bands and that the lowest unoccupied states have the primarily Co 3d character, respectively. These findings suggest the importance of the Co 3d electronic structures in determining TE properties of these Co-based oxides.

引用

页码：1127 / 1131

页数：5

共 30 条

[1] 2P X-RAY ABSORPTION OF 3D TRANSITION-METAL COMPOUNDS - AN ATOMIC MULTIPLET DESCRIPTION INCLUDING THE CRYSTAL-FIELD [J].

DEGROOT, FMF ;

FUGGLE, JC ;

THOLE, BT ;

SAWATZKY, GA .

PHYSICAL REVIEW B, 1990, 42 (09) :5459-5468

[2] Crystal structure and possible charge ordering in one-dimensional Ca3Co2O6 [J].

Fjellvag, H ;

Gulbrandsen, E ;

Aasland, S ;

Olsen, A ;

Hauback, BC .

JOURNAL OF SOLID STATE CHEMISTRY, 1996, 124 (01) :190-194

[3] Large in-plane anisotropy on resistivity and thermopower in the misfit layered oxide Bi2-xPbxSr2Co2Oy [J].

Fujii, T ;

Terasaki, I ;

Watanabe, T ;

Matsuda, A .

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, 2002, 41 (7A) :L783-L786

[4] High-temperature thermoelectric properties of NaxCoO2-δ single crystals [J].

Fujita, K ;

Mochida, T ;

Nakamura, K .

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 2001, 40 (07) :4644-4647

[5] Thermoelectric properties of Bi2Sr2Co2Ox polycrystalline materials [J].

Funahashi, R ;

Matsubara, I ;

Sodeoka, S .

APPLIED PHYSICS LETTERS, 2000, 76 (17) :2385-2387

[6] Different look at the spin state of Co3+ ions in a CoO5 pyramidal coordination -: art. no. 207402 [J].

Hu, Z ;

Wu, H ;

Haverkort, MW ;

Hsieh, HH ;

Lin, HJ ;

Lorenz, T ;

Baier, J ;

Reichl, A ;

Bonn, I ;

Felser, C ;

Tanaka, A ;

Chen, CT ;

Tjeng, LH .

PHYSICAL REVIEW LETTERS, 2004, 92 (20) :207402-1

[7]

Hufner S., 1995, Photoelectron Spectroscopy, V82

[8] Electronic structure of single-crystalline thermoelectric Bi2-xPbxSr2Co2Oy (x=0,0.6) from photoemission and x-ray absorption [J].

Kang, J. -S. ;

Han, S. W. ;

Fujii, T. ;

Terasaki, I. ;

Lee, S. S. ;

Kim, G. ;

Olson, C. G. ;

Lee, H. G. ;

Kim, J. -Y. ;

Min, B. I. .

PHYSICAL REVIEW B, 2006, 74 (20)

[9] Valence and spin states in delafossite AgNiO2 and the frustrated Jahn-Teller system ANiO2 (A=Li,Na) [J].

Kang, J. -S. ;

Lee, S. S. ;

Kim, G. ;

Lee, H. J. ;

Song, H. K. ;

Shin, Y. J. ;

Han, S. W. ;

Hwang, C. ;

Jung, M. C. ;

Shin, H. J. ;

Kim, B. H. ;

Kwon, S. K. ;

Min, B. I. .

PHYSICAL REVIEW B, 2007, 76 (19)

[10]

Kang JS, 2002, PHYS REV B, V66, DOI 10.1103/PhysRevB.66.113105

← 1 2 3 →