Laser-excited ultrahigh-resolution photoemission spectroscopy of NaxCoO2•yH2O:: Evidence for pseudogap formation -: art. no. 020505

被引：26

作者：

Shimojima, T ^{[1
]}

Yokoya, T

Kiss, T

Chainani, A

Shin, S

Togashi, T

Watanabe, S

Zhang, C

Chen, CT

Takada, K

Sasaki, T

Sakurai, H

Takayama-Muromachi, E

机构：

[1] Univ Tokyo, Inst Solid State Phys, Chiba 2778581, Japan

[2] SPring 8, RIKEN, Kobe, Hyogo 6795148, Japan

[3] Chinese Acad Sci, Beijing Ctr Crystal R&D, Beijing 100080, Peoples R China

[4] Natl Inst Mat Sci, Adv Mat Lab, Tsukuba, Ibaraki 3050044, Japan

[5] Natl Inst Mat Sci, Superconducting Mat Ctr, Tsukuba, Ibaraki 3050044, Japan

来源：

PHYSICAL REVIEW B | 2005年 / 71卷 / 02期

关键词：

D O I：

10.1103/PhysRevB.71.020505

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We have studied the temperature (T)-dependent electronic structure near the Fermi level of the layered cobaltate superconductor, Na0.35CoO2.1.3H(2)O, and related materials, using laser-excited ultrahigh-resolution photoemission spectroscopy. We observe the formation of a pseudogap (PG) with an energy scale of similar to20 meV in Na0.35CoO2.1.3H(2)O and Na0.35CoO2.0.7H(2)O, which is clearly absent in Na0.7CoO2. The energy scale of the PG is larger than the expected value for the superconducting gap, suggesting an additional competing order parameter at low T. We discuss implications of the PG in relation to available transport and magnetic susceptibility results.

引用

页数：4

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