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arXiv 0909.0479cond-mat.supr-concond-mat.str-el
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不均匀性和有限尺寸效应对Beresinkii-Kosterlitz-无磁超导转变的展宽

Broadening of the Beresinkii-Kosterlitz-Thouless superconducting transition by inhomogeneity and finite-size effects

L. Benfatto, C. Castellani, T. Giamarchi

摘要:

讨论了二维超导体中有限尺寸效应和非均匀性对Beresinkii-Kosterlitz-BKT相变的影响。特别是,我们专注于电阻率的温度依赖性,这是占主导地位的超导波动以上的BKT转变温度$T_{BKT}$和不均匀性低于它。通过重整化群的方法,我们建立了一个直接对应的参数值之间的关系,用于描述的BKT波动制度和$T_{BKT}$和平均场金-朗道转变温度之间的距离。在$T_{BKT}$以下,由于有限尺寸效应和不均匀性,出现了电阻尾部,这也反映了超流密度的温度依赖性。我们将我们的结果应用到最近的实验数据在超导LaAlO $_3$ /SrTiO $_3$异质结构,我们提取了一些信息的微观性质的系统,从我们的BKT拟合参数。最后,我们比较我们的方法,最近的数据分析在文献中,在BKT公式中的参数值的物理意义往往被忽视。

英文摘要:

We discuss the crucial role played by finite-size effects and inhomogeneity on the Beresinkii-Kosterlitz-Thouless (BKT) transition in two-dimensional superconductors. In particular, we focus on the temperature dependence of the resistivity, that is dominated by superconducting fluctuations above the BKT transition temperature $T_{BKT}$ and by inhomogeneity below it. By means of a renormalization-group approach we establish a direct correspondence between the parameter values used to describe the BKT fluctuation regime and the distance between $T_{BKT}$ and the mean-field Ginzburg-Landau transition temperature. Below $T_{BKT}$ a resistive tail arises due to finite-size effect and inhomogeneity, that reflects also on the temperature dependence of the superfluid density. We apply our results to recent experimental data in superconducting LaAlO$_3$/SrTiO$_3$ heterostructures, and we extract several informations on the microscopic properties of the system from our BKT fitting parameters. Finally, we compare our approach to recent data analysis presented in the literature, where the physical meaning of the parameter values in the BKT formulas has been often overlooked.

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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