论文标题
在加压bafe $ _2 $ s $ _3 $和bafe $ _2 $ s $ s $ _ {2.5} $ se $ se $ _ {0.5} $
Non-superconducting electronic ground state in pressurized BaFe$_2$S$_3$ and BaFe$_2$S$_{2.5}$Se$_{0.5}$
论文作者
论文摘要
我们通过中子衍射，无弹性中子散射，高压同步器衍射和高压运输技术，报告了一项对自旋梯子化合物$ _2 $ _2 $ s $ _2 $ s $ _ {2.5} $ _ {2.5} $ _ {2.5} $ _ {2.5} $的全面研究的全面研究。我们发现Bafe $ _2 $ s $ _ {2.5} $ se $ _ {0.5} $具有与BAFE $ _2 $ _2 $ s $ _3 $相同的$ cmcm $结构和条纹的抗磁性订单，但降低了n {é} eL = 98 $ kn = 98 $ k的订单，并略有下降。 1.40 $μ_b$每铁。 Bafe $ _2 $ s $ _ {2.5} $ SE $ _ {0.5} $中的低能旋转激发同样类似于Bafe $ _2 $ S $ _ {3} $的低功能。但是，与Bafe $ _2 $ S $ _3 $ t_c \ sim 14 $ 〜k的报告不同，在10〜GPA或更多的压力下，我们没有观察到Bafe $ _2 $ _2 $ s $ _ {2.5} $ _ {2.5} $ se $ _ {0.5} $ _ {0.5} $ _ {0.5} $在任何压力上以上压力向上to -to -to -to -to -19.7〜gpa。相反，在压力下，电阻率在低温下表现出上涨。此外，我们表明，为这项研究合成的其他BAFE $ _2 $ S $ _3 $的其他高质量样品同样无法在压力下变得超导，而是在低温下表现出类似的电阻率。这些结果表明，微观，特定于样品的细节在确定此自旋梯子系统中的最终电子基态方面起着重要作用。我们建议，在Bafe $ _2 $ _2 $ S $ _3 $和BAFE $ _2 $ S $ _ {2.5} $ SE $ _ {0.5} $中，电阻率上升的电阻率在低温下的电阻率上升。
We report a comprehensive study of the spin ladder compound BaFe$_2$S$_{2.5}$Se$_{0.5}$ using neutron diffraction, inelastic neutron scattering, high pressure synchrotron diffraction, and high pressure transport techniques. We find that BaFe$_2$S$_{2.5}$Se$_{0.5}$ possesses the same $Cmcm$ structure and stripe antiferromagnetic order as does BaFe$_2$S$_3$, but with a reduced N{é}el temperature of $T_N=98$ K compared to 120 K for the undoped system, and a slightly increased ordered moment of 1.40$μ_B$ per iron. The low-energy spin excitations in BaFe$_2$S$_{2.5}$Se$_{0.5}$ are likewise similar to those observed in BaFe$_2$S$_{3}$. However, unlike the reports of superconductivity in BaFe$_2$S$_3$ below $T_c \sim 14$~K under pressures of 10~GPa or more, we observe no superconductivity in BaFe$_2$S$_{2.5}$Se$_{0.5}$ at any pressure up to 19.7~GPa. In contrast, the resistivity exhibits an upturn at low temperature under pressure. Furthermore, we show that additional high-quality samples of BaFe$_2$S$_3$ synthesized for this study likewise fail to become superconducting under pressure, instead displaying a similar upturn in resistivity at low temperature. These results demonstrate that microscopic, sample-specific details play an important role in determining the ultimate electronic ground state in this spin ladder system. We suggest that the upturn in resistivity at low temperature in both BaFe$_2$S$_3$ and BaFe$_2$S$_{2.5}$Se$_{0.5}$ may result from Anderson localization induced by S vacancies and random Se substitutions, enhanced by the quasi-one-dimensional ladder structure.
