Characteristic two-dimensional Fermi surface topology of high-Tc iron-based superconductors

Masanori Sunagawa; Toshihiko Ishiga; Koji Tsubota; Taihei Jabuchi; Junki Sonoyama; Keita Iba; Kazutaka Kudo; Minoru Nohara; Kanta Ono; Hiroshi Kumigashira; Tomohiro Matsushita; Masashi Arita; Kenya Shimada; Hirofumi Namatame; Masaki Taniguchi; Takanori Wakita; Yuji Muraoka; Takayoshi Yokoya

doi:10.1038/srep04381

Characteristic two-dimensional Fermi surface topology of high-Tc iron-based superconductors

Sci Rep. 2014 Mar 14:4:4381. doi: 10.1038/srep04381.

Authors

Masanori Sunagawa¹, Toshihiko Ishiga¹, Koji Tsubota¹, Taihei Jabuchi¹, Junki Sonoyama¹, Keita Iba², Kazutaka Kudo², Minoru Nohara², Kanta Ono³, Hiroshi Kumigashira³, Tomohiro Matsushita⁴, Masashi Arita⁵, Kenya Shimada⁵, Hirofumi Namatame⁵, Masaki Taniguchi⁵, Takanori Wakita¹, Yuji Muraoka¹, Takayoshi Yokoya¹

Affiliations

¹ 1] The Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan [2] Research Laboratory for Surface Science, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan.
² 1] The Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan [2] Department of Physics, Okayama University, Okayama 700-8530, Japan.
³ Institute for Material Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801.
⁴ Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan.
⁵ Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-0046, Japan.

Abstract

Unconventional Cooper pairing originating from spin or orbital fluctuations has been proposed for iron-based superconductors. Such pairing may be enhanced by quasi-nesting of two-dimensional electron and hole-like Fermi surfaces (FS), which is considered an important ingredient for superconductivity at high critical temperatures (high-Tc). However, the dimensionality of the FS varies for hole and electron-doped systems, so the precise importance of this feature for high-Tc materials remains unclear. Here we demonstrate a phase of electron-doped CaFe2As2 (La and P co-doped CaFe2As2) with Tc = 45 K, which is the highest Tc found for the AEFe2As2 bulk superconductors (122-type; AE = Alkaline Earth), possesses only cylindrical hole- and electron-like FSs. This result indicates that FS topology consisting only of two-dimensional sheets is characteristic of both hole- and electron-doped 122-type high-Tc superconductors.

Publication types

Research Support, Non-U.S. Gov't