A Triplet Resonance in Superconducting Fe1.03Se0.4Te0.6

Juanjuan Liu; A T Savici; G E Granroth; K Habicht; Y Qiu; Jin Hu; Z Q Mao; Wei Bao

doi:10.1088/0256-307x/35/12/127401

A Triplet Resonance in Superconducting Fe_1.03Se_0.4Te_0.6

Chin Phys Lett. 2018;35(12):10.1088/0256-307x/35/12/127401. doi: 10.1088/0256-307x/35/12/127401.

Authors

Juanjuan Liu¹, A T Savici², G E Granroth², K Habicht³, Y Qiu^{4

5}, Jin Hu⁶, Z Q Mao⁷, Wei Bao¹

Affiliations

¹ Department of Physics, Renmin University of China, Beijing 100872.
² Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
³ Helmholtz-Zentrum Berlin für Materialen und Energy, Berlin D-14109, Germany.
⁴ NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
⁵ Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA.
⁶ Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA.
⁷ Department of Physics, Pennsylvania State University, University Park, PA 16802, USA.

Abstract

From heavy fermion compounds and cuprates to iron pnictides and chalcogenides, a spin resonance at $ℏ Ω_{0} \propto k_{B} T_{c}$ is a staple of nearly magnetic superconductors. Possible explanations include a two-particle bound state or loss of magnon damping in the superconducting state. While both scenarios suggest a central role for magnetic fluctuations, distinguishing them is important to identify the right theoretical framework to understand these types of unconventional superconductors. Using an inelastic neutron scattering technique, we show that the spin resonance in the optimally doped Fe_1.03Se_0.4Te_0.6 superconductor splits into three peaks in a high magnetic field, a signature of a two-particle S=1 triplet bound state.

Keywords: 74.20.Mn; 74.25.Ha; 74.70.–b; 78.70.Nx.

Grants and funding

9999-NIST/ImNIST/Intramural NIST DOC/United States