arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0810.2523cond-mat.str-el
收藏

近藤机制下量子点的光吸收和光发射

Optical absorption and emission of a quantum dot in the Kondo regime

Partha Goswami, Garima Puneyani, Avinashi Kapoor

摘要:

研究了描述量子点局域态(c态)与费米海导带杂化的Anderson模型的一个变体。我们证明,作为杂交参数V的函数,系统经历了从导带和C级完全耦合的状态到这些被解耦的状态的交叉。然而,c-电子光谱,有一个间隙,在前一个状态的近藤峰的存在。对于后者,我们有一个莫特样的本地化的c-电子光谱再次有一个没有近藤峰的间隙。在这个间隙内,传导电子完全恢复自由带态密度,有效杂化几乎为零。然而,我们的主要目的是研究具有强关联Kondo基态的量子点的发射和吸收。为此,我们使用格林函数运动方程方法。我们计算的吸收/发射(A/E)光谱在近藤政权通过对称化的量子自相关函数直接在微扰理论使用费米黄金法则近似。光谱揭示了一个尖锐的,高的峰接近Kondo-Abrikosov-Suhl峰和一些较小的,可区分的两侧。前者清楚地表明,近藤现象有其影响的A/E(非近藤过程),这是由耦合涉及的量子点跃迁的偶极矩反映的物理结构的点,包括限制势,在近藤制度。

英文摘要:

A variant of the Anderson model, that describes hybridization between localized state (c-state) of a quantum dot and a Fermi sea conduction band, is investigated. We demonstrate that, as a function of the hybridization parameter v, the system undergoes a crossover from the state where the conduction band and the c-level are fully coupled to a state where these are decoupled. The c-electron spectrum, however, has a gap together with the presence of the Kondo peak in the former state. For the latter, we have a Mott-like localization where the c-electron spectrum again has a gap without the Kondo peak. Within this gap the conduction electrons fully recover the free band density of states and the effective hybridization is practically zero. Our main aim, however, is to study the emission and absorption in a quantum dot with strongly correlated Kondo ground state. We use the Green function equation of motion method for this purpose. We calculate the absorption/emission (A/E) spectrum in the Kondo regime through a symmetrized quantum autocorrelation function obtainable directly within perturbation theory using the Fermi golden rule approximation. The spectrum reveals a sharp, tall peak close to Kondo-Abrikosov-Suhl peak and a few smaller, distinguishable ones on either side. The former clearly indicates that the Kondo phenomenon has its impact on A/E (non-Kondo processes), which are driven by the coupling involving the dipole moment of quantum dot transitions reflecting the physical structure of the dot including the confinement potential, in the Kondo regime.

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。

↑