Enhancement of the Kondo temperature of magnetic impurities in metallic point contacts due to the fluctuations of the local density of states Abstract The effect of local density of states (LDOS) fluctuations on the dynamics of a Kondo impurities in a small metallic point contact (PC) is studied. To estimate the spatial and energy dependent LDOS fluctuations we investigate a model PC by means o...

We discuss models of interacting magnetic impurities coupled to a metallic host, which show one or more boundary quantum phase transitions where the ground-state spin changes as a function of the interimpurity couplings. The simplest example is realized by two spin1 2 Kondo impurities coupled to a single orbital of the host. We investigate the phase diagram and crossover behavior of this model ...

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In a number of fermion systems, the quasiparticle density of states varies near the Fermi energy like |E−EF |r, where r = 1 or 2. The effect of magnetic impurities in such systems is studied via a perturbative renormalization-group treatment of the n-channel Kondo model, carried out to third order in the antiferromagnetic exchange coupling J . For 0 < r < 1/2n, a (multichannel) Kondo effect occ...

Recently, there has been a resurgence of intense experimental and theoretical interest on the Kondo physics of nanoscopic and mesoscopic systems due to the possibility of making experiments in extremely small samples. We have carried out exact diagonalization calculations to study the effect of energy spacing ∆ in the conduction band states, hybridization, number of electrons, and disorder on t...

We theoretically study the Kondo effect in a quantum dot embedded in an Aharonov-Bohm ring, using the "poor man's" scaling method. Analytical expressions of the Kondo temperature TK are given as a function of magnetic flux Φ penetrating the ring. In this Kondo problem, there are two characteristic lengths, Lc=ℏvF∕|ε̃0| and LK = ħvF = TK, where vF is the Fermi velocity and ε̃0 is the renormalized ...