Thorsten Schmitt-Photon Science Division, Swiss Light Source,Paul Scherrer Institut, SWITZERLAND

Описание: Titled: SPIN-EXCITATION ANISOTROPY IN THENEMATIC STATE OF DETWINNED FeSe
Abstract: The origin of the electronic nematicity,which is characterized by rotational symmetry breaking, in FeSe is one of the most important unresolved puzzles in the study of iron-based superconductors. In both spin-and orbital-nematic models, the intrinsic magnetic excitations at Q1= 1, 0 and Q2= 0, 1 of twin-free FeSe are expected to provide decisive criteria for clarifying this issue. Although a spin-fluctuation anisotropy below 10 meV between Q1and Q2has been observed by inelastic neutron scattering around Tc 9 K Ts 90 K, it remains unclear whether such an anisotropy also persists at higher energies and associates with the nematic transition Ts. Here we use resonant inelastic x-ray scattering at the Fe L3-edge to probe the high-energy magnetic excitations of uniaxial-strain detwinned FeSe [1].A prominent anisotropy between the magnetic excitations along the Hand Kdirections is found to persist to 200 meV. This anisotropy decreases gradually with increasing temperature and finally vanishes at a temperature around Ts. Our results reveal an unprecedented strong spin excitation anisotropy with a large energy scale well above the dxz/dyzorbital splitting, suggesting that the nematic phase transition is primarily spin-driven[1].
References:
[1]Xingye Lu, Wenliang Zhang, Yi Tseng, Ruixian Liu, Zhen Tao, Eugenio Paris, Panpan Liu, Tong Chen, Vladimir Strocov, Yu Song, Rong Yu, Qimiao Si, Pengcheng Dai, Thorsten Schmitt,Nature Physics18, 806–812 2022