Warshauer Jacob A, Bustamante Lopez Daniel Alejandro, Dong Qingxin, Chen Genfu, Hu Wanzheng
Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, 02215 MA, USA.
Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, 8 Zhongguancun 3rd South Street, 100190 Beijing, China.
PNAS Nexus. 2023 May 16;2(6):pgad164. doi: 10.1093/pnasnexus/pgad164. eCollection 2023 Jun.
Iron-based superconductors provide a rich platform to investigate the interplay between unconventional superconductivity, nematicity, and magnetism. The electronic structure and the magnetic properties of iron-based superconductors are highly sensitive to the pnictogen height. Coherent excitation of the phonon by femtosecond laser directly modulates the pnictogen height, which has been used to control the physical properties of iron-based superconductors. Previous studies show that the driven phonon resulted in a transient increase of the pnictogen height in BaFeAs, favoring an enhanced Fe magnetic moment. However, there are no direct observations on either the enhanced Fe magnetic moments or the enhanced spin-density wave (SDW) gap. Here, we use time-resolved broadband terahertz spectroscopy to investigate the dynamics of BaFeAs in the phonon-driven state. Below the SDW transition temperature, we observe a transient gap generation at early-time delays. A similar transient feature is observed in the normal state up to room temperature.
铁基超导体为研究非常规超导性、向列性和磁性之间的相互作用提供了一个丰富的平台。铁基超导体的电子结构和磁性质对氮族元素高度高度敏感。飞秒激光对声子的相干激发直接调制了氮族元素高度，这已被用于控制铁基超导体的物理性质。先前的研究表明，受驱动的声子导致BaFeAs中氮族元素高度的瞬态增加，有利于增强铁磁矩。然而，对于增强的铁磁矩或增强的自旋密度波（SDW）能隙都没有直接观测结果。在这里，我们使用时间分辨宽带太赫兹光谱来研究声子驱动状态下BaFeAs的动力学。在SDW转变温度以下，我们在早期延迟时观察到一个瞬态能隙的产生。在高达室温的正常状态下也观察到了类似的瞬态特征。
