arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.04856cond-mat.supr-con
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第二类超导体涡旋晶格中的荷电

Charging in the vortex lattice of type-II superconductors

Marie Ohuchi, Hikaru Ueki, Takafumi Kita

摘要:

基于增广准经典方程,我们研究了磁场对$s$波超导体Abrikosov晶格中涡核电荷的影响.在增广准经典方程中,我们除了引入Lorentz力外,还引入了超导体中的电荷对-电势梯度(PPG)项.我们在$T=0.2 T_{\rm c}$和$0.5 T_{\rm c}$上的数值计算结果表明,在不同的磁场下,磁通线晶格上的电荷周期性重新分布具有不同的空间模式。PPG项在弱磁场下占主导地位,超过洛伦兹力,用于在涡核中积累电荷,而洛伦兹力在较高的磁场下占主导地位,从而在$H\sim \frac{1}{2}H_{{\rm c}2}$周围的核电荷中产生峰值结构。我们估计在$T=0.2 T_{\rm c}$的核心电荷的峰值,使用适合于铜酸盐的参数,以获得在$ab$平面中的半径$0.2 ξ_0$和沿$c$轴的长度$1 \ {\rm nm}$的核心区域中的大的$Q \sim 10^{-2} |e|$值。

英文摘要:

We study the magnetic-field dependence of the vortex-core charge in the Abrikosov lattice of an $s$-wave superconductor based on the augmented quasiclassical equations, where we incorporate the pair-potential gradient (PPG) terms characteristic of charging in superconductors besides the well-known Lorentz force. Our numerical results at $T=0.2 T_{\rm c}$ and $0.5 T_{\rm c}$ reveal that periodic charge redistribution is superimposed on the magnetic flux-line lattice with different spatial patterns at different fields. The PPG terms are dominant at weak fields over the Lorentz force for accumulating charge in the vortex cores, whereas the Lorentz force prevails at higher fields to give rise to a peak structure in the core charge around $H\sim \frac{1}{2}H_{{\rm c}2}$. We estimate the peak value of the core charge at $T=0.2 T_{\rm c}$ using parameters appropriate for cuprates to obtain a large value of $Q \sim 10^{-2} |e|$ in the core region of radius $0.2 ξ_0$ in the $ab$ plane and length $1 \ {\rm nm}$ along the $c$ axis.

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