arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1304.4342cond-mat.mes-hall
收藏

孤立无序金属极化率和退相的量子修正

Quantum Corrections to the Polarizability and Dephasing in Isolated Disordered Metals

M. Treiber, P. M. Ostrovsky, O. M. Yevtushenko, J. von Delft, I. V. Lerner

摘要:

利用扩散传播子中的环展开研究了孤立金属介观系统极化率的量子修正。我们发现,连接(巨正则系综)和孤立(正则系综)系统之间的差异只出现在子领先的条款的扩展,可以忽略不计,如果外部场的频率,$ω$,是(甚至略小于)的平均能级间距,$Δ$的顺序。如果是$ω\ll Δ$,则双环路校正变得很重要。我们通过系统地评估相应图的弹道部分(Hikami盒)和利用电中性来计算它。我们的理论允许一个考虑到有限的退相率,$γ$,由电子相互作用产生的,它是互补的随机矩阵理论(RMT)和$σ$ -模型,有效的在$γ\to 0$的组合获得的非微扰结果。值得注意的是,我们发现,两个环路的结果与中等弱的退相,$γ\sim Δ$,是类似的RMT+ $σ$ -模型的结果,即使在限制$ω\to 0$。对于较小的$γ$,我们讨论的可能性之间的微扰和非微扰的结果插值。我们比较我们的结果的温度依赖性的极化率的孤立环的Deblock \emph{et al}的实验数据[ \prl \ { \bf 84},5379(2000); \prb \ { \bf 65},075301(2002)],我们认为,难以捉摸的0 D制度的退相可能已经表现在所观察到的磁振荡。此外,我们深入讨论了未来可能的极化率测量,这可能旨在揭示存在的0 D退相和泡利阻塞在小温度下的作用。

英文摘要:

We study the quantum corrections to the polarizability of isolated metallic mesoscopic systems using the loop-expansion in diffusive propagators. We show that the difference between connected (grand-canonical ensemble) and isolated (canonical ensemble) systems appears only in subleading terms of the expansion, and can be neglected if the frequency of the external field, $ω$, is of the order of (or even slightly smaller than) the mean level spacing, $Δ$. If $ω\ll Δ$, the two-loop correction becomes important. We calculate it by systematically evaluating the ballistic parts (the Hikami boxes) of the corresponding diagrams and exploiting electroneutrality. Our theory allows one to take into account a finite dephasing rate, $γ$, generated by electron interactions, and it is complementary to the non-perturbative results obtained from a combination of Random Matrix Theory (RMT) and the $σ$-model, valid at $γ\to 0$. Remarkably, we find that the two-loop result for isolated systems with moderately weak dephasing, $γ\sim Δ$, is similar to the result of the RMT+$σ$-model even in the limit $ω\to 0$. For smaller $γ$, we discuss the possibility to interpolate between the perturbative and the non-perturbative results. We compare our results for the temperature dependence of the polarizability of isolated rings to the experimental data of Deblock \emph{et al} [\prl \ {\bf 84}, 5379 (2000); \prb \ {\bf 65}, 075301 (2002)], and we argue that the elusive 0D regime of dephasing might have manifested itself in the observed magneto-oscillations. Besides, we thoroughly discuss possible future measurements of the polarizability, which could aim to reveal the existence of 0D dephasing and the role of the Pauli blocking at small temperatures.

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。

↑