Antiferroic electronic structure in the nonmagnetic superconducting state of the iron-based superconductors

作者：Shimojima Takahiro^*; Malaeb Walid; Nakamura Asuka; Kondo Takeshi; Kihou Kunihiro; Lee Chul Ho; Iyo Akira; Eisaki Hiroshi; Ishida Shigeyuki; Nakajima Masamichi; Uchida Shin ichi; Ohgushi Kenya; Ishizaka Kyoko; Shin Shik^*

来源：Science Advances, 2017, 3(8): e1700466.

DOI：10.1126/sciadv.1700466

A major problem in the field of high-transition temperature (T-c) superconductivity is the identification of the electronic instabilities near superconductivity. It is known that the iron-based superconductors exhibit antiferromagnetic order, which competes with the superconductivity. However, in the nonmagnetic state, there are many aspects of the electronic instabilities that remain unclarified, as represented by the orbital instability and several in-plane anisotropic physical properties. We report a new aspect of the electronic state of the optimally doped iron-based superconductors by using high-energy resolution angle-resolved photoemission spectroscopy. We find spectral evidence for the folded electronic structure suggestive of an antiferroic electronic instability, coexisting with the superconductivity in the nonmagnetic state of Ba1-xKxFe2As2. We further establish a phase diagram showing that the antiferroic electronic structure persists in a large portion of the nonmagnetic phase covering the superconducting dome. These results motivate consideration of a key unknown electronic instability, which is necessary for the achievement of high-T-c superconductivity in the iron-based superconductors.

• 出版日期2017-8