Direct Observation of the Spin Exciton in Andreev Spectroscopy of Iron-Based Superconductors期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

Direct Observation of the Spin Exciton in Andreev Spectroscopy of Iron-Based Superconductors

Authors:	Maxim M. Korshunov Svetoslav A. Kuzmichev Tatiana E. Kuzmicheva

Affiliation:	1.Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Akademgorodok, 660036 Krasnoyarsk, Russia;2.Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia;3.Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia

Abstract:	Quasiparticle excitations provide viable information on the physics of unconventional superconductors. Higgs and Leggett modes are some of the classic examples. Another important bosonic excitation is the spin exciton originating from the sign-changing superconducting gap structure. Here we report a direct observation of the temperature-dependent spin exciton in the Andreev spectra of iron-based superconductors. Combined with the other experimental evidence, our observation confirms the extended s-wave ( $s_{\pm}$ ) order parameter symmetry and indirectly proves the spin-fluctuation mechanism of Cooper pairing.

Keywords:	unconventional superconductivity spin-fluctuation mechanism of Cooper pairing spin resonance peak Andreev spectroscopy planar break-junction iron-based superconductors