TY  - JOUR
AU  - Shen, Shoudong
AU  - Zhang, Xiaowen
AU  - Wo, Hongliang
AU  - Shen, Yao
AU  - Feng, Yu
AU  - Schneidewind, A.
AU  - Čermák, P.
AU  - Wang, Wenbin
AU  - Zhao, Jun
TI  - Neutron Spin Resonance in the Heavily Hole-Doped KFe 2 As 2 Superconductor
JO  - Physical review letters
VL  - 124
IS  - 1
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2020-01343
SP  - 017001
PY  - 2020
AB  - We report high-resolution neutron scattering measurements of the low energy spin fluctuations ofKFe2As2, the end member of the hole-doped Ba1−xKxFe2As2family with only hole pockets, above andbelow its superconducting transition temperatureTc(∼3.5K). Our data reveal clear spin fluctuations at theincommensurate wave vector (0.5δ,0,L), (δ¼0.2) (1-Fe unit cell), which exhibitL-modulationpeaking atL¼0.5. Upon cooling to the superconducting state, the incommensurate spin fluctuationsgradually open a spin gap and form a sharp spin resonance mode. The incommensurability (2δ¼0.4)ofthe resonance mode (∼1.2meV) is considerably larger than the previously reported value (2δ≈0.32)athigher energies (≥∼6meV). The determination of the momentum structure of spin fluctuation in the lowenergy limit allows a direct comparison with the realistic Fermi surface and superconducting gap structure.Our results point to ans-wave pairing with a reversed sign between the hole pockets near the zone center inKFe2As2.
LB  - PUB:(DE-HGF)16
C6  - pmid:31976731
UR  - <Go to ISI:>//WOS:000505496400003
DO  - DOI:10.1103/PhysRevLett.124.017001
UR  - https://juser.fz-juelich.de/record/874252
ER  -