Structural and Magnetic Phase Transitions near Optimal Superconductivity in BaFe2(As1-xPx)2
Structural and Magnetic Phase Transitions near Optimal Superconductivity in BaFe2(As1-xPx)2
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BaFe2(As1−xPx)2 接近最佳超导性的结构和磁相变
DOI：
10.1103/physrevlett.114.157002
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发表时间：
2015-04-17
影响因子：
8.6
通讯作者：
Dai, Pengcheng
中科院分区：
文献类型：
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作者：
Hu, Ding;Lu, Xingye;Dai, Pengcheng
我们利用核磁共振 (NMR)、高分辨率 X 射线和中子散射研究来研究磷掺杂 BaFe2(As1-xPx)(2) 的结构和磁性相变。先前的输运、核磁共振、比热和磁穿透深度测量为 x = 0.3 处接近最佳超导性的量子临界点 (QCP) 的存在提供了令人信服的证据。然而，我们表明，BaFe2(As1-xPx)(2) 中的四方结构到斜方结构 (T-s) 和顺磁到反铁磁 (AF、T-N) 的转变总是耦合的，并且在 x = 0.29 时接近 T-N 近似于 T-s >= T-c （大约 29 K），然后在 x >= 0.3 时突然消失。这些结果表明，BaFe2(As1-xPx)(2) 中的 AF 级在接近最佳超导性时以弱一阶方式消失，就像避免 QCP 的电子掺杂铁磷族化物一样。
We use nuclear magnetic resonance (NMR), high-resolution x-ray, and neutron scattering studies to study structural and magnetic phase transitions in phosphorus-doped BaFe2(As1-xPx)(2). Previous transport, NMR, specific heat, and magnetic penetration depth measurements have provided compelling evidence for the presence of a quantum critical point (QCP) near optimal superconductivity at x = 0.3. However, we show that the tetragonal-to-orthorhombic structural (T-s) and paramagnetic to antiferromagnetic (AF, T-N) transitions in BaFe2(As1-xPx)(2) are always coupled and approach T-N approximate to T-s >= T-c (approximate to 29 K) for x = 0.29 before vanishing abruptly for x >= 0.3. These results suggest that AF order in BaFe2(As1-xPx)(2) disappears in a weakly first-order fashion near optimal superconductivity, much like the electron-doped iron pnictides with an avoided QCP.