Strongly correlated zero-bias anomaly in double quantum dot measurements

TL;DR

This paper explores the origin of zero-bias anomalies in strongly correlated systems, demonstrating how double quantum dot measurements can reveal detailed transition mechanisms responsible for these anomalies.

Contribution

It links the kinetic-energy-driven zero-bias anomaly in two-site systems to mesoscopic double quantum dot experiments, providing new insights into correlated electron behavior.

Findings

Zero-bias anomaly width scales with intersite hopping t

Double quantum dots can probe ensemble-average density of states

Measurements reveal transition details causing the anomaly

Abstract

Experiments in doped transition metal oxides often show suppression in the single-particle density of states at the Fermi level, but disorder-induced zero-bias anomalies in strongly correlated systems remain poorly understood. Numerical studies of the Anderson-Hubbard model have identified a zero-bias anomaly that is unique to strongly correlated materials, with a width proportional to the intersite hopping amplitude t [S. Chiesa, P. B. Chakraborty, W. E. Pickett, and R. T. Scalettar, Phys. Rev. Lett. 101, 086401 (2008)]. In ensembles of two-site systems, a zero-bias anomaly with the same parameter dependence also occurs, suggesting a similar physical origin [R. Wortis and W. A. Atkinson, Phys. Rev. B 82, 073107 (2010)]. We describe how this kinetic-energy-driven zero-bias anomaly in ensembles of two-site systems may be seen in a mesoscopic realization based on double quantum dots. Moreover, the double-quantum-dot measurements provide access not only to the ensemble-average density of states but also to the details of the transitions which give rise to the zero-bias anomaly.