Strong local moment antiferromagnetic spin fluctuations in V-doped LiFeAs

Zhuang Xu; Guangyang Dai; Yu Li; Zhiping Yin; Yan Rong; Long Tian; Panpan Liu; Hui Wang; Lingyi Xing; Yuan Wei; Ryoichi Kajimoto; Kazuhiko Ikeuchi; D. L. Abernathy; Xiancheng Wang; Changqing Jin; Xingye Lu; Guotai Tan; Pengcheng Dai

arXiv · 1912.11860

Strong local moment antiferromagnetic spin fluctuations in V-doped LiFeAs

Zhuang Xu·Guangyang Dai·Yu Li·Zhiping Yin·Yan Rong·Long Tian·Panpan Liu·Hui Wang·Lingyi Xing·Yuan Wei·Ryoichi Kajimoto·Kazuhiko Ikeuchi·D. L. Abernathy·Xiancheng Wang·Changqing Jin·Xingye Lu·Guotai Tan·Pengcheng Dai

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Abstract

We use neutron scattering to study vanadium (hole)-doped LiFe$_{1-x}$V$_x$As. In the undoped state, LiFeAs exhibits superconductivity at $T_c=18$ K and transverse incommensurate spin excitations similar to electron overdoped iron pnictides. Upon vanadium-doping to form LiFe$_{0.955}$V$_{0.045}$, the transverse incommensurate spin excitations in LiFeAs transform into longitudinally elongated in a similar fashion as that of potassium (hole) doped Ba$_{0.7}$K$_{0.3}$Fe$_2$As$_2$, but with dramatically enhanced magnetic scattering and elimination of superconductivity. This is different from the suppression of the overall magnetic excitations in hole doped BaFe$_2$As$_2$ and the enhancement of superconductivity near optimal hole doping. These results are consistent with density function theory plus dynamic mean field theory calculations, suggesting that vanadium-doping in LiFeAs may induce an enlarged effective magnetic moment $S_{eff}$ with a spin crossover ground state arising from the inter-orbital scattering of itinerant electrons.

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Zhuang Xu, Guangyang Dai, Yu Li, Zhiping Yin, Yan Rong, Long Tian, Panpan Liu, Hui Wang, Lingyi Xing, Yuan Wei, Ryoichi Kajimoto, Kazuhiko Ikeuchi, D. L. Abernathy, Xiancheng Wang, Changqing Jin, Xingye Lu, Guotai Tan, Pengcheng Dai. 2019-12-26. Strong local moment antiferromagnetic spin fluctuations in V-doped LiFeAs. https://arxiv.org/abs/1912.11860

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