Study of high pressure electronic state on iron-oxynictide high-T_C superconductors using as probe for thermoelectric effect

热电效应探针铁氮氧化物高温超导体高压电子态研究

• 批准号: 21740260
• 负责人: HEDO Masato
• 金额: $ 2.75万
• 依托单位: University of the Ryukyus
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Young Scientists (B)
• 财政年份: 2009
• 资助国家: 日本
• 起止时间: 2009 至 2010
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21740260/
• 关键词: 高圧力; ゼーベック効果; 鉄ヒ素系超伝導体; 電子状態; 鉄ヒ素超伝導体

Seebeck coefficient (S/T) of Eu_<0.5>Ca_<0.5>Fe_2As_2 showed sign inversion before appearance of superconducting state (SC) and it was found that state of Fermi surface was notably transmuted just before expression of SC. In the case of EuFe_2As_2 verifying precursor phenomenon of SC, the S/T may change positive with further increasing pressure after negative to zero of S/T and it is expected to present similar behavior of Eu_<0.5>Ca_<0.5>Fe_2As_2. For EuFe_2As_2 and Eu_<0.5>Ca_<0.5>Fe_2As_2, T_2-dependence coefficient A of resistivity was prominently decrease after emergence of SC, it is able to understand that the density of state around Fermi level is distinct decrease above critical pressure P_C in this system.

Eu_Ca_Fe_2As_2的Seebeck系数（S/T）<0.5><0.5>在超导态（SC）出现之前出现符号反转，并且在SC出现之前费米面的状态发生了显著的变化。在EuFe_2As_2的情况下，证实了SC的先驱现象，S/T在负到零之后，随着压力的进一步增加可能会变为正，并有望呈现类似于Eu_Ca_Fe_2As_2的行为<0.5><0.5>。对于EuFe_2As_2和<0.5>Eu_Ca_Fe_2As_2<0.5>，超导体出现后，电阻率的T_2依赖系数A显著减小，可以理解在临界压力P_C以上，费米能级附近的态密度明显减小。

项目成果

Possible Existence of Magnetic Polaron in Nearly Ferromagnetic Semiconductor β-US_2

近铁磁半导体β-US_2中可能存在磁极化子

• 发表时间: 2009
• 期刊: Journal of Physical Society of Japan 78
• 作者: S.Ikeda;et al.,
• 通讯作者: et al.,