Temperature dependence of electronic transport through molecular magnets in the Kondo regime

Abstract

The effects of finite temperature in transport through nanoscopic systems exhibiting uniaxial magnetic anisotropy D, such as molecular magnets, adatoms, or quantum dots side-coupled to a large spin are analyzed in the Kondo regime. The linear-response conductance is calculated by means of the full density-matrix numerical renormalization group method as a function of temperature T, magnetic anisotropy D, and exchange coupling J between the molecule's core spin and the orbital level. It is shown that such system displays a two-stage Kondo effect as a function of temperature and a quantum phase transition as a function of the exchange coupling J. Moreover, additional peaks are found in the linear conductance for temperatures of the order of T\sim|J| and T\simD. It is also shown that the conductance variation with T remarkably depends on the sign of the exchange coupling J.