Ginzburg-Landau approach to the vortex–domain wall interaction in superconductors with nematic order
Ginzburg-Landau approach to the vortex–domain wall interaction in superconductors with nematic order
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DOI：
10.1103/physrevb.109.094513
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发表时间：
2024-01
影响因子：
3.7
通讯作者：
R. Severino;P. Mininni;Eduardo Fradkin;V. Bekeris;G. Pasquini;Gustavo Lozano
中科院分区：
文献类型：
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作者：
R. Severino;P. Mininni;Eduardo Fradkin;V. Bekeris;G. Pasquini;Gustavo Lozano
在这项工作中，我们在金兹堡-朗道方法的框架内研究了涡旋和向列域壁之间的相互作用。系统的自由能用s波超导的复序参数特征和与向列性相关的实（伊辛型）序参数来表示。两阶参数之间的相互作用用双二次导数项和三线性导数项来描述。为了研究这些相互作用的影响，我们使用高性能的伪谱方法求解了随时间变化的耗散金兹堡朗道方程，通过该方法我们计算了涡旋的轨迹，在不同的耦合参数下，被壁面吸引或排斥，以及壁面动力学。我们证明，尽管它很简单，但该理论显示了在铁基超导体中观察到的许多实验现象。特别是，我们发现双二次项的符号决定了相互作用的吸引（拉平）或排斥（反拉平）特征，分别在FeSe和BaFeCoAs化合物中观察到。三线性项负责漩涡核心的椭圆形状，以及椭圆轴和漩涡轨迹相对于结构晶格轴的方向。对于缩紧的情况，我们发现漩涡核心可以用一个心形结构来描述，这与FeSe中进行的STM实验一致。
In this work we study the interaction between vortices and nematic domain walls within the framework of a Ginzburg Landau approach. The free energy of the system is written in terms of a complex order parameter characteristic of $s$-wave superconductivity and a real (Ising type) order parameter associated to nematicity. The interaction between both order parameters is described by a biquadratic and a trilinear derivative term. To study the effects of these interactions we solve the time-dependent dissipative Ginzburg Landau equations using a highly performant pseudospectral method by which we calculate the trajectories of a vortex that, for different coupling parameters, is either attracted or repelled by a wall, as well as of the wall dynamics. We show that despite its simplicity, this theory displays many phenomena observed experimentally in Fe-based superconductors. In particular we find that the sign of the biquadratic term determines the attractive (pining) or repulsive (antipining) character of the interaction, as observed in FeSe and BaFeCoAs compounds respectively. The trilinear term is responsible for the elliptical shape of vortex cores as well as for the orientation of the axes of the ellipses and vortex trajectories with respect to the axes of the structural lattice. For the case of pining, we show that the vortex core is well described by a heart-shaped structure in agreement with STM experiments performed in FeSe.