Collective modes in pumped unconventional superconductors with competing ground states
Collective modes in pumped unconventional superconductors with competing ground states
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DOI：
10.1103/physrevb.100.140501
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发表时间：
2019-07
影响因子：
3.7
通讯作者：
Marvin A. Müller;P. Volkov;I. Paul;I. Eremin
中科院分区：
文献类型：
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作者：
Marvin A. Müller;P. Volkov;I. Paul;I. Eremin
受太赫兹抽运探测实验发展的启发，我们研究了具有多个吸引对通道的超导体中的短时动力学。以自旋-自旋相互作用下的单带正方晶格模型为例，在抽运脉冲激发后，在谱隙和准粒子分布的短时动力学中，我们发现了成对对称性的集体激发（称为Bardasis-Schrieffer模）以及序参量振幅（Higgs模）的特征.我们表明，脉冲的偏振和强度可以用来控制非平衡态的对称性，以及不同的集体模式的贡献的频率和相对强度。我们发现特别强的签名的Bardasis-Schrieffer模式的准粒子分布函数的动态。我们的工作显示了现代超快实验解决非常规超导体集体激发的潜力，并强调了次主导相互作用对这些系统中非平衡动力学的重要性。
Motivated by the recent development of terahertz pump-probe experiments, we investigate the short-time dynamics in superconductors with multiple attractive pairing channels. Studying a single-band square lattice model with spin-spin interaction as an example, we find the signatures of collective excitations of the pairing symmetries (known as Bardasis-Schrieffer modes) as well as the order parameter amplitude (Higgs mode) in the short-time dynamics of the spectral gap and quasiparticle distribution after an excitation by a pump pulse. We show that the polarization and intensity of the pulse can be used to control the symmetry of the non-equilibrium state as well as frequencies and relative intensities of the contributions of different collective modes. We find particularly strong signatures of the Bardasis-Schrieffer mode in the dynamics of the quasiparticle distribution function. Our work shows the potential of modern ultrafast experiments to address the collective excitations in unconventional superconductors and highlights the importance of sub-dominant interactions for the non-equilibrium dynamics in these systems.