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arXiv 1709.03369cond-mat.supr-concond-mat.stat-mech
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强钉扎条件下II型超导体的涡旋动力学

Vortex dynamics in type II superconductors under strong pinning conditions

A. U. Thomann, V. B. Geshkenbein, G. Blatter

摘要:

我们研究了强钉扎情况下钉扎对II型超导体涡旋晶格动力学的影响,并结合解析和数值方法确定了力-速度(或电流-电压)特性。我们的分析涉及一个小密度$n_p$的缺陷,大的力$f_p$的旋涡,从而诱导的强钉扎理论的一个特征的配置。我们确定了与速度有关的平均钉扎力密度$\langle F_p(v)\rangle$,并发现它在速度尺度$v_p \sim f_p/ηa_0^3$上变化,其中$η$是旋涡运动的粘性,$a_0$是旋涡之间的距离。在小的针密度限制下,该速度远大于在接近临界力密度$F_c = \langle F_p(v=0)\rangle \propto n_p f_p$的驱动器处自由涡系统的典型流速$v_c \sim F_c/η$。其结果是,我们发现一个通用的过剩力特性,一个几乎线性的力-速度特性的临界力-密度$F_c$转移;线性通量流制度,只有在大型驱动器接近。我们的分析提供了一个推导库仑定律的干摩擦的情况下,强涡钉扎。

英文摘要:

We study effects of pinning on the dynamics of a vortex lattice in a type II superconductor in the strong-pinning situation and determine the force--velocity (or current--voltage) characteristic combining analytical and numerical methods. Our analysis deals with a small density $n_p$ of defects that act with a large force $f_p$ on the vortices, thereby inducing bistable configurations that are a characteristic feature of strong pinning theory. We determine the velocity-dependent average pinning-force density $\langle F_p(v)\rangle$ and find that it changes on the velocity scale $v_p \sim f_p/ηa_0^3$, where $η$ is the viscosity of vortex motion and $a_0$ the distance between vortices. In the small pin-density limit, this velocity is much larger than the typical flow velocity $v_c \sim F_c/η$ of the free vortex system at drives near the critical force-density $F_c = \langle F_p(v=0)\rangle \propto n_p f_p$. As a result, we find a generic excess-force characteristic, a nearly linear force--velocity characteristic shifted by the critical force-density $F_c$; the linear flux-flow regime is approached only at large drives. Our analysis provides a derivation of Coulomb's law of dry friction for the case of strong vortex pinning.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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