Effect of Strong Correlations on the Disorder-Induced Zero Bias Anomaly in the Two-Site Anderson-Hubbard Model

Abstract

Several recent exact diagonalization calculations have established that the Anderson-Hubbard model has a disorder-induced zero bias anomaly (ZBA) (also called a disorder-induced pseudogap) in the density of states. In order to understand the physics of the ZBA, we study a simplified problem---an ensemble of two-site molecules with random site energies---for which analytical results are possible. For this ensemble, we examine how the ZBA forms in both the weakly correlated (mean field) and strongly correlated limits. In the weakly correlated case, the ZBA can be understood as the result of level repulsion between bonding and antibonding molecular orbitals. A similar level repulsion occurs in the strongly correlated case too, but a larger contribution to the ZBA comes from the suppression of a triplet excitation mode. This inherently many-body mechanism does not have a counterpart in mean-field models.

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References in corpus (3)

• Single-particle excitations under coexisting electron correlation and disorder: a numerical study of the Anderson-Hubbard model
• Soft Hubbard gaps in disordered itinerant models with short-range interaction
• Disorder-Induced Stabilization of the Pseudogap in Strongly Correlated Systems

Cited by in corpus (8)

• Local integrals of motion in the two-site Anderson-Hubbard model
• Variational Monte Carlo Study of Anderson Localization in the Hubbard Model
• Energy dependence of localization with interactions and disorder: The generalized inverse participation ratio of an ensemble of two-site Anderson-Hubbard systems
• Analysis of the Disorder-Induced Zero Bias Anomaly in the Anderson-Hubbard Model
• Temperature dependence of the zero-bias anomaly in the Anderson-Hubbard model: Insights from an ensemble of two-site systems
• Effect of nonlocal interactions on the disorder-induced zero-bias anomaly in the Anderson-Hubbard model
• Understanding disorder-induced zero-bias anomalies in systems with short-range interactions: An atomic-limit perspective
• Strongly correlated zero-bias anomaly in double quantum dot measurements