The thermodynamic and magnetic properties of a single impurity Anderson model that describes Ce in an environment with hexagonal symmetry is treated within the noncrossing approximation. It is found that the properties of the system at temperatures larger than the crystal field splitting are described by a Kondo temperature of the sixfold-degenerate spin-orbit multiplet and at low temperatures ...

We discuss the universal theory of localized impurities in the paramagnetic state of 2D antiferromagnets where the spin gap is assumed to be significantly smaller than a typical exchange energy. We study the impurity spin susceptibility near the host quantum transition from a gapped paramagnet to a Néel state, and we compute the impurity-induced damping of the spin-1 mode of the gapped antiferr...

We introduce a method to obtain the specific heat of quantum impurity models via a direct calculation of the impurity internal energy requiring only the evaluation of local quantitieswithin a single numerical renormalization group (NRG) calculation for the total system. For the Anderson impurity model we show that the impurity internal energy can be expressed as a sum of purely local static cor...

We introduce a partial state fidelity approach to quantum phase transitions. We consider a superconducting lattice with a magnetic impurity inserted at its centre, and look at the fidelity between partial (either one-site or two-site) quantum states. In the vicinity of the point of the quantum phase transition, we observe a sudden drop of the fidelity between two one-site partial states corresp...

Electronic and structural properties of substitutional group-V donors sN, P, As, Sbd and group-III acceptors sB, Al, Ga, Ind in silicon nanocrystals with hydrogen passivation are explored using first-principles calculations based on hybrid density functional theory with complete geometrical optimization. The bonding near the impurity is similar to that found for the impurity in bulk crystalline...

2014 The effect of a point scattering potential on the properties of a nearly half filled narrow energy-band is studied in the limit of strong intra-atomic Coulomb repulsions. The potential needed to localize a state depends on the spin configuration. A localized hole is found to stabilize a ferromagnetic polarization within a few atomic distances from the impurity. The strength of this couplin...

Zeeman splitting of the ground state of single impurities in the quantum well of a resonant tunneling heterostructure is reported. We determine the absolute magnitude of the effective magnetic spin splitting factor g ' for a single impurity in a 44 Å Al0.27Ga0.73AsyGaAsyAl0.27Ga0.73As quantum well to be 0.28 6 0.02. This system also allows for independent measurement of the electron tunneling r...

Trace impurity transport in tokamaks is studied using an electrostatic, collisionless fluid model for Ion-Temperature-Gradient (ITG) and Trapped-Electron (TE) mode driven turbulence in the presence of radio frequency (rf) fields in the ion cyclotron range of frequencies, and the results are compared with neoclassical predictions. Two separate effects of the rf field on ITG/TE-mode stability and...