arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1004.4178cond-mat.str-elcond-mat.mes-hall
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关联系统的电导:有限系统中的实时动力学

Conductance of correlated systems: real-time dynamics in finite systems

Alexander Branschädel, Guenter Schneider, Peter Schmitteckert

摘要:

用含时密度矩阵重整化群(td-DMRG)方法计算输运态的时间演化,已被证明是计算与非相互作用一维导线耦合的相互作用杂质系统的线性和有限偏压电导的有力工具。几种模型,包括相互作用共振能级模型(IRLM),单杂质安德森模型(SIAM),以及不同的多网站结构的模型,已在这方面的调查的主题。在这项工作中,我们给出了一个概述的不同的数值方法,已成功地应用到这个问题,并进入相当详细的评论时,我们已被用来获得完整的I-V特性的IRLM的技术。使用的模型组成的扩展相互作用的纳米结构连接到非相互作用的引线的无自旋费米子,我们解释的方法,我们使用的电流-电压特性和讨论的有限尺寸效应,必须考虑到。我们报告的线性和有限的偏置电导通过一个七个网站的结构,弱和强的最近邻相互作用的结果。在非相互作用的限制与精确的对角化结果的比较作为我们的方法的准确性的验证。最后,我们讨论了通过应用阻尼边界有效扩大有限系统的可能性,并给出了在这种情况下可以预期的有效系统大小和精度的估计。

英文摘要:

Numerical time evolution of transport states using time dependent Density Matrix Renormalization Group (td-DMRG) methods has turned out to be a powerful tool to calculate the linear and finite bias conductance of interacting impurity systems coupled to non-interacting one-dimensional leads. Several models, including the Interacting Resonant Level Model (IRLM), the Single Impurity Anderson Model (SIAM), as well as models with different multi site structures, have been subject of investigations in this context. In this work we give an overview of the different numerical approaches that have been successfully applied to the problem and go into considerable detail when we comment on the techniques that have been used to obtain the full I--V-characteristics for the IRLM. Using a model of spinless fermions consisting of an extended interacting nanostructure attached to non-interacting leads, we explain the method we use to obtain the current--voltage characteristics and discuss the finite size effects that have to be taken into account. We report results for the linear and finite bias conductance through a seven site structure with weak and strong nearest-neighbor interactions. Comparison with exact diagonalisation results in the non-interacting limit serve as a verification of the accuracy of our approach. Finally we discuss the possibility of effectively enlarging the finite system by applying damped boundaries and give an estimate of the effective system size and accuracy that can be expected in this case.

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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