Direct observation of superconducting gaps in iron-based superconductors by laser ARPES

10th International Conference on Materials and Mechanisms of Superconductivity

Okazaki, Kozo^1

Institute for Solid State Physics (ISSP), University of Tokyo, Chiba 277-8581 Kashiwa, Japan^1

关键词: Angle resolved photoemission spectroscopy;    Direct observations;    Energy resolutions;    Momentum-dependent;    Superconducting coherence;    Superconducting gaps;    Temperature dependent;    Ultra-high energies;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/449/1/012019/pdf
DOI  :  10.1088/1742-6596/449/1/012019

来源: IOP

【 摘 要 】

We have developed a new apparatus for carrying out ultra-high energy resolution laser-excited angle-resolved photoemission spectroscopy (laser ARPES). The achieved energy resolution is ∼ 70 μeV at a sample temperature ∼ 1.5 K. As a test case, we have measured the superconducting gap of elemental metal Sn (Tc 3.7 K). We have used this laser-ARPES apparatus, to directly observe the superconducting gap of various iron-based superconductors. The spectra of FeTe0.6Se0.4 below Tc show a very clear temperature dependent superconducting coherence peak. Preliminary momentum-dependent results indicate an anisotropic superconducting gap in FeTe0.6Se0.4.