Neutron Spin Resonance in the Heavily Hole-doped KFe$_{2}$As$_{2}$ Superconductor
| Autor: | Shen, Shoudong, Zhang, Xiaowen, Wo, Hongliang, Shen, Yao, Feng, Yu, Schneidewind, A., Čermák, P., Wang, Wenbin, Zhao, Jun |
|---|---|
| Rok vydání: | 2019 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.124.017001 |
| Popis: | We report high-resolution neutron scattering measurements of the low energy spin fluctuations of KFe$_{2}$As$_{2}$, the end member of the hole-doped Ba$_{1-x}$K$_x$Fe$_2$As$_2$ family with only hole pockets, above and below its superconducting transition temperature $T_c$ ($\sim$ 3.5 K). Our data reveals clear spin fluctuations at the incommensurate wave vector ($0.5\pm\delta$, 0, $L$), ($\delta$ = 0.2)(1-Fe unit cell), which exhibit $L$-modulation peaking at $L=0.5$. Upon cooling to the superconducting state, the incommensurate spin fluctuations gradually open a spin-gap and form a sharp spin resonance mode. The incommensurability ($2\delta$ = 0.4) of the resonance mode ($\sim1.2$ meV) is considerably larger than the previously reported value ($2\delta$ $\approx0.32$) at higher energies ($\ge\sim6$ meV). The determination of the momentum structure of spin fluctuation in the low energy limit allows a direct comparison with the realistic Fermi surface and superconducting gap structure. Our results point to an $s$-wave pairing with a reversed sign between the hole pockets near the zone center in KFe$_{2}$As$_{2}$. Comment: Accepted for publication in Physical Review Letters |
| Databáze: | arXiv |
| Externí odkaz: |
|