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arXiv 0905.0198cond-mat.mes-hall
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介观持续电流的对断裂效应

Pair-breaking effect on mesoscopic persistent currents

Hamutal Bary-Soroker, Ora Entin-Wohlman, Yoseph Imry

摘要:

我们考虑超导涨落对正常金属环系综介观持续电流(PC)的贡献,该环系综由超导材料制成,其低裸转变温度$T^{0}_{c}$远小于无扰动能量$E_{c}$ .以磁性杂质为例,介绍了电子对破缺的影响。我们发现,在一个相当宽的范围内的对断裂强度$\hbar/τ_{s}$,使$T_c^0 \lesssim \hbar/τ_s \lesssim E_c$,超导转变温度被归一化到分钟值或零,而PC几乎不受影响。这可以解释铜和金的平均PC值的大小,以及确定其$T^0_c$的方法。分析了电流和主导超导涨落对$E_cτ_s$和$E_c$与温度之比的依赖关系。在铜(金)中测得的PC对应于几个(一部分)mK的$T^0_c$。

英文摘要:

We consider the contribution of superconducting fluctuations to the mesoscopic persistent current (PC) of an ensemble of normal metallic rings, made of a superconducting material whose low bare transition temperature $T^{0}_{c}$ is much smaller than the Thouless energy $E_{c}$. The effect of pair breaking is introduced via the example of magnetic impurities. We find that over a rather broad range of pair-breaking strength $\hbar/τ_{s}$, such that $T_c^0 \lesssim \hbar/τ_s \lesssim E_c$, the superconducting transition temperature is normalized down to minute values or zero while the PC is hardly affected. This may provide an explanation for the magnitude of the average PC's in copper and gold, as well as a way to determine their $T^0_c$'s. The dependence of the current and the dominant superconducting fluctuations on $E_cτ_s$ and on the ratio between $E_c$ and the temperature is analyzed. The measured PC's in copper (gold) correspond to $T^0_c$ of a few (a fraction of) mK.

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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