Kondo effect in interacting nanoscopic systems: Keldysh field integral theory
Kondo effect in interacting nanoscopic systems: Keldysh field integral theory
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DOI：
10.1103/physrevb.84.235314
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发表时间：
2011-09
影响因子：
3.7
通讯作者：
S. Smirnov;M. Grifoni
中科院分区：
文献类型：
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作者：
S. Smirnov;M. Grifoni
非平衡相互作用纳米尺度器件中的近藤物理是一种具有广泛应用前景的多粒子基本现象。由于其巨大的复杂性，清晰灵活的理论仍然是非常可取的。我们开发了一个物理上透明的分析理论，能够正确地描述近藤效应在强相互作用系统的温度接近和高于近藤温度。我们推导出一个非平衡Keldysh场理论有效的系统与任何有限的电子-电子相互作用，这是远远强于系统的耦合接触。有限的电子-电子相互作用被视为涉及尽可能多的奴隶玻色子自由度，因为一个具体的多体系统的需要。在一个小的附近的零从玻色子场配置弱从玻色子振荡，引起的点接触隧穿，描述了一个有效的Keldysh作用二次从玻色子场。为了清楚起见，理论是为单杂质安德森模型，但凯尔迪什场积分的建设是普遍的，适用于系统更复杂的多体光谱。
Kondo physics in nonequilibrium interacting nanoscale devices is an attractive fundamental many-particle phenomenon with a rich potential for applications. Due to enormous complexity its clear and flexible theory is still highly desirable. We develop a physically transparent analytical theory capable to correctly describe the Kondo effect in strongly interacting systems at temperatures close to and above the Kondo temperature. We derive a nonequilibrium Keldysh field theory valid for a system with any finite electron-electron interaction which is much stronger than the coupling of the system to contacts. Finite electron-electron interactions are treated involving as many slave-boson degrees of freedom as one needs for a concrete many-body system. In a small vicinity of the zero slave-bosonic field configuration weak slave-bosonic oscillations, induced by the dot-contacts tunneling, are described by an effective Keldysh action quadratic in the slave-bosonic fields. For clarity the theory is presented for the single impurity Anderson model but the construction of the Keldysh field integral is universal and applicable to systems with more complex many-body spectra.