Construction of ultrahigh-resolution photoemission spectrometer with small spot size using laser as a photon source

以激光为光子源构建小光斑超高分辨率光电子能谱仪

• 批准号: 12440098
• 负责人: SHIN Shik
• 金额: $ 9.86万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440098/
• 关键词: Soft x-ray laser; ultrahigh-resolutioin PES; PES with small spot size; low-Te superconductor; superconducting gap; anisotropic superconductivity; 高分解能光電子分光; 超伝導体; 電子状態

We have constructed a low-temperature and high-resolution photoemission (PE) spectrometer for using a laser as a photon source. We have achieved an energy resolution of 0.8 meV without an energy width of light\ an angular resolution of 0.2 degree, and the lowest sample temperature of 4 K, which are the highest performance of PE spectrometer in the world.Using this spectrometer, we have studied superconductors with a low transition temperature (low-Tc). We have observed a superconducting gap of elemental metals (Nb and Pb) as well as phonon-induced fine structures in Pb. We have concluded anisotropic s-wave superconductivity for Yni_2B_2C from an impurity-induced change in gap anisotropy. We have provided a spectroscopic evidence for a multiple gap of MgB_2. We have measured an isotropic s-wave gap and a normal-state pseudogap in Ba_<1-x>K_xBiO_3. We have observed the superconducting gap of Ba_8Si_<46> and classified it as a weak coupling superconductor. From angle-resolved study of 2H-NbSe_2, we have resolved all the Fermi surface sheets predicted by band structure calculations and have observed FS sheet dependent superconductivity.

我们已经建立了一个低温和高分辨率的光电子能谱（PE）使用激光作为光子源。在没有光的能量宽度的情况下，我们获得了0.8meV的能量分辨率，0.2度的角分辨率，最低样品温度为4K，这是目前世界上性能最好的PE谱仪，我们用它研究了低转变温度（low-Tc）超导体。我们观察到了元素金属（Nb和Pb）的超导能隙以及Pb中声子诱导的精细结构。从杂质引起的禁带各向异性的变化，我们得出了YNi_2B_2C的各向异性s波超导电性。为MgB_2的多重能隙提供了光谱证据。我们测量了Ba_ K_xBiO_3晶体的各向同性s波带隙和正常态赝带隙<1-x>。我们观察到Ba_8Si_3的超导能隙<46>，并将其归类为弱耦合超导体。通过对2 H-NbSe_2的角分辨研究，我们解决了所有由能带结构计算预测的费米面片，并观察到了FS片依赖的超导电性。

项目成果

S.Tsuda, T.Yokoya, T.Kiss, Y.Takano, K.Togano, H.Kito, H.Ihara, S.Shin: "Evidence for a multiple superconducting gap in MgB_2 from high-resolution photoemission spectroscopy"Phys. Rev. Lett.. 85. 177006 (2001)

S.Tsuda、T.Yokoya、T.Kiss、Y.Takano、K.Togano、H.Kito、H.Ihara、S.Shin：“来自高分辨率光电子能谱的 MgB_2 中多重超导能隙的证据”

S. Tsuda, T. Yokoya, T. Kiss, Y. Takano, K. togano, H. Kito, H. Ihara and S. Shin: "Evidence for a multiple superconducting gap in MgB_2 from high-resolution photoemissio spectroscopy"Phys. Rev. Lett.. 87. 177006 (2001)

S. Tsuda、T. Yokoya、T. Kiss、Y. Takano、K. togano、H. Kito、H. Ihara 和 S. Shin：“来自高分辨率光电子能谱的 MgB_2 中多重超导能隙的证据”

A. Chainani, T. Yokoya, T. Kiss, S. Shin, T. nishio, and H. Uwo: "Elecdtron-phonon coupling induced pseudogap and the superconducting transition in Ba_<0.67>K_<0.33>BiO_3"Phys. Rev. B. 64. 180509R (2001)

A. Chainani、T. Yokoya、T. Kiss、S. Shin、T. nishio 和 H. Uwo：“电子-声子耦合引起的赝能隙和 Ba_<0.67>K_<0.33>BiO_3 中的超导转变”Phys。

K.Kanai: "Ulrahigh-resolution photoemission and rosonant-inverse photoemission spectroscopy on CePd_3"Journal of Electron spectroscopy and Related Phenomena. (in press).

K.Kanai：“CePd_3 上的超高分辨率光电子发射和谐振反光电子能谱”《电子能谱和相关现象杂志》。

T.Yokoya et al.: "Electronic structure and superconducting gap of silicon clathrate Ba_8Si_<46> studied with ultrahigh-resolution photoemission spectroscopy"Phys. Rev. B. 64. 172504 (2001)

T.Yokoya等：“用超高分辨率光电子能谱研究硅包合物Ba_8Si_<46>的电子结构和超导能隙”Phys.