2018/08/13 by Yue Sun, Shunichiro Kittaka, Shota Nakamura +9 · 16 citations
Biochemistry, Genetics and Molecular Biology · Materials Science · Physics and Astronomy · #Amyloidosis: Diagnosis, Treatment, Outcomes #Business #Iron-based superconductors research #Materials science #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.98.064505
published in Physical review. B./Physical review. B 98(6) (American Physical Society) · 7 pages, 4 figures
openalex publication_date 2018/08/13 · arxiv created 2018/08/16 · arxiv updated 2018/08/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate the band structure, nematic state, and superconducting gap structure of two selected FeSe single crystals containing different amounts of disorder. Transport and angle-resolved photoemission spectroscopy measurements show that the small amount of disorder has little effect on the band structure and the nematic state of FeSe. However, temperature and magnetic field dependencies of specific heat for the two samples are quite different. Wave-vector-dependent gap structure is obtained from the three-dimensional field-angle-resolved specific heat measurements. A small gap with two vertical-line nodes or gap minima along the kz direction is found only in the sample with higher quality. Such symmetry-unprotected nodes or gap minima are found to be smeared out by a small amount of disorder, and the gap becomes isotropic in the sample of lower quality. Our study reveals that the reported controversy on the gap structure of FeSe is due to the disorder-sensitive nodelike small gap.