arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2012.01051cond-mat.supr-con
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空穴掺杂Ba $_{1-x}$(K,Na)$_x$ Fe $_2$ As $_2$和Sr $_{1-x}Na$ _x PDMATHAAAE_2 $As$ _2$的声子谱软弹性常数

Soft elastic constants from phonon spectroscopy in hole-doped Ba$_{1-x}$(K,Na)$_x$Fe$_2$As$_2$ and Sr$_{1-x}Na$_x$Fe$_2$As$_2$

M. Kauth, S. Rosenkranz, A. H. Said, K. M. Taddei, Th. Wolf, F. Weber

摘要:

我们报告了非弹性X射线散射测量的平面内偏振横向声学声子模式传播沿$q\parallel$ [100]在各种空穴掺杂的化合物属于122家庭的铁基超导体。该声子模式的色散的斜率与$q \rightarrow 0$极限中的剪切模量$C_{66}$的平方根成比例,因此对这些化合物中发生的四方晶到正交晶结构相变敏感。与Ba(Fe $_{0.94}$ Co $_{0.06}$)$_2$作为$_2$ [F. Weber等人,物理评论B 98,014516(2018)],我们发现从我们的实验中推导出的$C_{66}$值与在最佳掺杂下Ba $_{1-x}$(K,Na)$_x$ Fe $_2$ As $_2$中杨氏模量测量值之间的定性一致性。这些结果提供了一个上限约50 μ m的最佳空穴掺杂化合物的π相关长度。此外,我们还研究了在较低掺杂水平下表现出正交磁性相的化合物,其中$C_{66}$不能通过体积探针接近,以及C4四元磁性相。

英文摘要:

We report inelastic x-ray scattering measurements of the in-plane polarized transverse acoustic phonon mode propagating along $q\parallel$[100] in various hole-doped compounds belonging to the 122 family of iron-based superconductors. The slope of the dispersion of this phonon mode is proportional to the square root of the shear modulus $C_{66}$ in the $q \rightarrow 0$ limit and, hence, sensitive to the tetragonal-to-orthorhombic structural phase transition occurring in these compounds. In contrast to a recent report for Ba(Fe$_{0.94}$Co$_{0.06}$)$_2$As$_2$ [F. Weber et al., Phys. Rev. B 98, 014516 (2018)], we find qualitative agreement between values of $C_{66}$ deduced from our experiments and those derived from measurements of the Youngs modulus in Ba$_{1-x}$(K,Na)$_x$Fe$_2$As$_2$ at optimal doping. These results provide an upper limit of about 50 Å for the nematic correlation length for the optimally hole-doped compounds. Furthermore, we also studied compounds at lower doping levels exhibiting the orthorhombic magnetic phase, where $C_{66}$ is not accessible by volume probes, as well as the C4 tetragonal magnetic phase.investigated

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