Dichotomy between orbital and magnetic nematic instabilities in BaFe2S3
Dichotomy between orbital and magnetic nematic instabilities in BaFe2S3
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DOI：
10.1103/physrevresearch.2.043293
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发表时间：
2020-11-30
影响因子：
4.2
通讯作者：
Shibauchi, T.
中科院分区：
文献类型：
--
作者：
Hosoi, S.;Aoyama, T.;Shibauchi, T.
向列序几乎普遍出现在铁基超导体中，但由于轨道和磁涨落之间的密切耦合，阐明其起源具有挑战性。铁基梯形材料BaFe2S3在压力下超导，在T-N以下（类似于117 K）表现出反铁磁有序，在T*（类似于180 K）表现出弱电阻率异常，其性质仍然难以捉摸。在这里，我们报告了 BaFe2S3 中的角度分辨磁阻 (MR) 和弹性电阻 (ER) 测量，揭示了 T * 时的明显变化。我们发现，MR 各向异性和 ER 向列响应在 T * 附近均受到抑制，这意味着促进各向同性电子态的轨道有序在 T * 处稳定。这种低于 T * 的各向同性状态与反铁磁序竞争，向列涨落的非单调温度依赖性证明了这一点。与铁磷族化物中自旋和轨道通道中的协作向列序相反，目前的竞争序可以提供替代平台来识别轨道和磁波动的单独作用。
Nematic orders emerge nearly universally in iron-based superconductors, but elucidating their origins is challenging because of intimate couplings between orbital and magnetic fluctuations. The iron-based ladder material BaFe2S3, which superconducts under pressure, exhibits antiferromagnetic order below T-N similar to 117 K and a weak resistivity anomaly at T * similar to 180 K, whose nature remains elusive. Here we report angle-resolved magnetoresistance (MR) and elastoresistance (ER) measurements in BaFe2S3, which reveal distinct changes at T *. We find that MR anisotropy and ER nematic response are both suppressed near T *, implying that an orbital order promoting isotropic electronic states is stabilized at T *. Such an isotropic state below T * competes with the antiferromagnetic order, which is evidenced by the nonmonotonic temperature dependence of nematic fluctuations. In contrast to the cooperative nematic orders in spin and orbital channels in iron pnictides, the present competing orders can provide an alternative platform to identify the separate roles of orbital and magnetic fluctuations.