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arXiv 1306.1244cond-mat.supr-concond-mat.stat-mech
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二维II型超导体相变的性质

On the nature of the phase transitions in two-dimensional type II superconductors

Niels R. Walet, M. A. Moore

摘要:

我们模拟了II型超导体薄膜中涡旋的热力学。我们做了最低朗道能级近似,并使用了准周期边界条件。我们的工作是一致的,与以前的模拟结果,其中的证据被发现为一个明显的一阶过渡之间的涡旋液态和涡旋晶体状态。然而,我们表明,这些结果只是一个人工制品的研究系统太小。使用传统方法模拟较大的系统有很大的困难。通过最佳能量扩散算法,我们已经能够研究包含多达约1000个涡旋的系统,并且对于这些较大的系统,一阶转变的证据消失。通过研究晶体和六角序,我们表明,KTHNY的情况似乎适用,从晶体熔化是第一个六角液态和旁边的正常涡旋液体,在这两种情况下,通过连续过渡。

英文摘要:

We have simulated the thermodynamics of vortices in a thin film of a type-II superconductor. We make the lowest Landau level approximation, and use quasi-periodic boundary conditions. Our work is consistent with the results of previous simulations where evidence was found for an apparent first order transition between the vortex liquid state and the vortex crystal state. We show, however, that these results are just an artifact of studying systems which are too small. There are substantial difficulties in simulating larger systems using traditional approaches. By means of the optimal energy diffusion algorithm we have been able to study systems containing up to about one thousand vortices, and for these larger systems the evidence for a first order transition disappears. By studying both crystalline and hexatic order, we show that the KTHNY scenario seems to apply, where melting from the crystal is first to the hexatic liquid state and next to the normal vortex liquid, in both cases via a continuous transition.

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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