Robust upward dispersion of the neutron spin resonance in the heavy fermion superconductor Ce1-xYbxCoIn5.
The neutron spin resonance is a collective magnetic excitation that appears in the unconventional copper oxide, iron pnictide and heavy fermion superconductors. Although the resonance is commonly associated with a spin-exciton due to the d(s±)-wave symmetry of the superconducting order parameter, it has also been proposed to be a magnon-like excitation appearing in the superconducting state. Here we use inelastic neutron scattering to demonstrate that the resonance in the heavy fermion superconductor Ce1-xYbxCoIn5with x=0, 0.05 and 0.3 has a ring-like upward dispersion that is robust against Yb-doping. By comparing our experimental data with a random phase approximation calculation using the electronic structure and the momentum dependence of the -wave superconducting gap determined from scanning tunnelling microscopy (STM) for CeCoIn5, we conclude that the robust upward-dispersing resonance mode in Ce1-xYbxCoIn5is inconsistent with the downward dispersion predicted within the spin-exciton scenario.
Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.
Yu
Y
Song
Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
John
J
Van Dyke
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.|Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.|Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA.
I K
IK
Lum
Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.|Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA.
B D
BD
White
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.|Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.|Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA.
Sooyoung
S
Jang
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.|Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.|Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA.
Duygu
D
Yazici
State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
L
L
Shu
Jülich Center for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany.
A
http://orcid.org/0000-0002-7239-9888
A
Schneidewind
Jülich Center for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, D-85747 Garching, Germany.
Petr
P
Čermák
NIST Center for Neutron Research, National Institute of Standard and Technology, Gaithersburg, Maryland 20899, USA.
Y
Y
Qiu
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.|Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.|Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA.
M B
MB
Maple
Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
Dirk K
DK
Morr
Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.
Pengcheng
http://orcid.org/0000-0002-6088-3170
P
Dai
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