Real-time renormalization group and cutoff scales in nonequilibrium applied to an arbitrary quantum dot in the Coulomb blockade regime

Article

关键词: KONDO;    IMPURITY;    ANDERSON;    BIAS;   

DOI  :  10.1103/PhysRevB.76.165316

来源: SCIE

【 摘 要 】

We apply the real-time renormalization group (RG) in nonequilibrium to an arbitrary quantum dot in the Coulomb blockade regime. Within one-loop RG equations, we include self-consistently the kernel governing the dynamics of the reduced density matrix of the dot. As a result, we find that relaxation and dephasing rates generically cut off the RG flow. In addition, we include all other cutoff scales defined by temperature, energy excitations, frequency, and voltage. We apply the formalism to transport through single molecular magnets, realized by the fully anisotropic Kondo model (with three different exchange couplings J(x), J(y), and J(z)) in a magnetic field h(z). We calculate the differential conductance as function of bias voltage V and discuss a quantum phase transition which can be tuned by changing the sign of J(x)J(y)J(z) via the anisotropy parameters. Finally, we calculate the noise S(Omega) at finite frequency Omega for the isotropic Kondo model and find that the dephasing rate determines the height of the shoulders in dS(Omega)/d Omega near Omega=V.

【 授权许可】

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