Spin Blockade, Orbital Occupation, and Charge Ordering in La1.5Sr0.5CoO4

被引：156

作者：

Chang, C. F. ^{[1
]}

Hu, Z. ^{[1
]}

Wu, Hua ^{[1
]}

Burnus, T. ^{[1
]}

Hollmann, N. ^{[1
]}

Benomar, M. ^{[1
]}

Lorenz, T. ^{[1
]}

Tanaka, A. ^{[2
]}

Lin, H. -J. ^{[3
]}

Hsieh, H. H. ^{[4
]}

Chen, C. T. ^{[3
]}

Tjeng, L. H. ^{[1
]}

机构：

[1] Univ Cologne, Inst Phys 2, D-50937 Cologne, Germany

[2] Hiroshima Univ, Dept Quantum Matter, ADSM, Higashihiroshima 7398530, Japan

[3] Natl Synchrotron Radiat Res Ctr, Hsinchu 30077, Taiwan

[4] Natl Def Univ, Chung Cheng Inst Technol, Tao Yuan 335, Taiwan

来源：

PHYSICAL REVIEW LETTERS | 2009年 / 102卷 / 11期

关键词：

ELECTRICAL-PROPERTIES; ELECTRONIC-STRUCTURE; MAGNETIC-PROPERTIES; STATE TRANSITION; LA2-XSRXCOO4; MAGNETORESISTANCE; PHOTOEMISSION; TEMPERATURE; LACOO3; 3D;

D O I：

10.1103/PhysRevLett.102.116401

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Using Co-L-2,L-3 and O-K x-ray absorption spectroscopy, we reveal that the charge ordering in La1.5Sr0.5CoO4 involves high spin (S=3/2) Co2+ and low spin (S=0) Co3+ ions. This provides evidence for the spin-blockade phenomenon as a source for the extremely insulating nature of the La2-xSrxCoO4 series. The associated e(g)(2) and e(g)(0) orbital occupation accounts for the large contrast in the Co-O bond lengths and, in turn, the high charge ordering temperature. Yet, the low magnetic ordering temperature is naturally explained by the presence of the nonmagnetic (S=0) Co3+ ions. From the identification of the bands we infer that La1.5Sr0.5CoO4 is a narrow band material.

引用

页数：4

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