Fluctuation-exchange approximation theory of the nonequilibrium singlet-triplet transition

Article

关键词: RENORMALIZATION-GROUP METHOD;    PERTURBATION EXPANSION;    CONSERVING APPROXIMATIONS;    ELECTRON-SYSTEMS;    QUANTUM-DOT;    CARBON NANOTUBES;    LDA++ APPROACH;    IMPURITY;    MODEL;    DENSITY;   

DOI  :  10.1103/PhysRevB.84.205117

来源: SCIE

【 摘 要 】

As a continuation of a previous work [B. Horvath et al., Phys. Rev. B 82, 165129 (2010)], here we extend the so-called fluctuation exchange approximation (FLEX) to study the nonequilibrium singlet-triplet transition. We show that, while being relatively fast and a conserving approximation, FLEX is able to recover all important features of the transition, including the evolution of the linear conductance throughout the transition, the two-stage Kondo effect on the triplet side, and the gradual opening of the singlet-triplet gap on the triplet side of the transition. A comparison with numerical renormalization-group calculations also shows that FLEX captures rather well the width of the Kondo resonance. FLEX thus offers a viable route to describe correlated multilevel systems under nonequilibrium conditions, and in its rather general form, as formulated here, it could find a broad application in molecular electronics calculations.

【 授权许可】

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