Dynamical instability with respect to finite-momentum pairing in quenched BCS superconducting phases
Dynamical instability with respect to finite-momentum pairing in quenched BCS superconducting phases
复制标题
淬火 BCS 超导相中有限动量配对的动态不稳定性
DOI：
10.1103/physrevb.99.014517
复制
发表时间：
2019-01-30
影响因子：
3.7
通讯作者：
Gong, Ming
中科院分区：
文献类型：
--
作者：
Huang, Beibing;Yang, Xiaosen;Gong, Ming
本文采用含时的真实的空间和动量空间的Bogoliubov-de Gennes方程方法和安德森赝自旋表示方法，数值研究了在Peierls替代下，Bardeen-Cooper-Schrieffer（BCS）对在淬灭相存在下的命运.这种相位印记可以通过调制超冷原子中的电场和太赫兹光泵浦脉冲照射固体中的常规和非常规超导体来实现。在弱相位印记的情况下，BCS对是稳定的，而在强相位印记的情况下，允许有限动量对的不稳定性，其中真实的空间方法和动量空间方法得到不同的结果.在脉冲规范势中，我们发现即使矢量势更强，这种不稳定性也不会发生。我们还表明，均匀和交错规范势产生不同的行为。当交错势诱导BCS对向过阻尼相转变时，均匀规范可以增强BCS对，而不会诱导过阻尼相。这些结果对于实现有限动量对，如具有动力学调制的Fulde-Ferrell-Larkin-Ovchinnikov相位，有一定的指导意义。
In this work we numerically investigate the fate of the Bardeen-Cooper-Schrieffer (BCS) pairing in the presence of quenched phase under Peierls substitution using time-dependent real space and momentum space Bogoliubov-de Gennes equation methods and Anderson pseudospin representation method. This kind of phase imprint can be realized by modulating electric field in ultracold atoms and illumining of THz optical pump pulse in solids with conventional and unconventional superconductors. In the case of weak phase imprint, the BCS pairing is stable; while in the strong phase imprint, instability towards finite-momentum pairing is allowed, in which the real space and momentum space methods yield different results. In the pulsed gauge potential, we find that this instability will not happen even with much stronger vector potential. We also show that the uniform and staggered gauge potentials yield different behaviors. While the staggered potential induces transition from the BCS pairing to over-damped phase, the uniform gauge may enhance the pairing and will not induce to the over-damped phase. These result may shade light on the realization of finite momentum pairing, such as Fulde-Ferrell-Larkin-Ovchinnikov phase with dynamical modulation.