Temperature dependence of the zero-bias anomaly in the Anderson–Hubbard model:insights from an ensemble of two-site systems

Abstract

Motivated by experiments on doped transition metal oxides, this paper considers theinterplay of interactions, disorder, kinetic energy and temperature in a simple system. Anensemble of two-site Anderson–Hubbard model systems has already been shown to displaya zero-bias anomaly (Wortis and Atkinson 2010 Phys. Rev. B 82 073107) whichshares features with that found in the two-dimensional Anderson–Hubbard model(Chiesa et al 2008 Phys. Rev. Lett. 101 086401). Here the temperature dependence ofthe density of states of this ensemble is examined. In the atomic limit, there isno zero-bias anomaly at zero temperature, but one develops at small nonzerotemperatures. With hopping, small temperatures augment the zero-temperaturekinetic-energy-driven zero-bias anomaly, while at larger temperatures the anomaly is filledin.