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.