Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 53: Poster Session: Superconductivity 1

TT 53.12: Poster

Mittwoch, 22. März 2017, 15:00–19:00, P2-OG2

Spin resonance of Ba_1−xK_xFe₂As₂ studied by neutron scattering — •Chul-Ho Lee¹, Kunihiro Kihou¹, Jitae Park², Kazumasa Horigane³, Florian Wasser⁴, Navid Qureshi⁵, Yvan Sidis⁶, Jun Akimitsu³, and Markus Braden⁴ — ¹AIST, Japan — ²MLZ, Germany — ³Okayama Univ., Japan — ⁴Universitat zu Koln, Germany — ⁵ILL, France — ⁶LLB, France

The remarkable enhancement of magnetic neutron scattering signals appearing in a superconducting phase, so called spin resonance, is important to examin since it could include information of Cooper pairing. Here, we examined the spin fluctuation of hole-doped Ba_1−xK_xFe₂As₂ by inelastic neutron scattering to clarify the doping dependence of spin resonance. Neutron scattering experiments were conducted using the triple-axis spectrometer PUMA at FRM ll, Germany and 2T1 at LLB, France. We have found that the behavior of the spin resonance dramatically changes around x = 0.66 [1]. Resonance peaks have been observed clearly below 2Δs in the optimum doping region, while they are absent in the overdoped region. Instead, there is a transfer of spectral weight from energies below 2Δs to higher energies, peaking at values of 3Δs for x = 0.84. These results indicate a reduced impact of magnetism on Cooper pair formation in the overdoped region.

[1] C. H. Lee et al., Sci. Rep. 6, 23424 (2016)