Quantum Phase Transitions in Models of Magnetic Impurities

Quantum phase transitions in models of coupled magnetic impurities

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 ...

Quantum Phase Transitions in Models of Magnetic Impurities

Zero temperature phase transitions not only occur in the bulk of quantum systems, but also at boundaries or impurities. We review recent work on quantum phase transitions in impurity models that are generalizations of the standard Kondo model describing the interaction of a localized magnetic moment with a metallic fermionic host. Whereas in the standard case the moment is screened for any anti...

Phase transitions in gapless Fermi systems with magnetic impurities.

Quantum Phase Transitions in Magnetic Systems

x

Quantum phase transitions of magnetic rotons.

Because of weak spin-orbit coupling and broken inversion symmetry the paramagnons of an itinerant, almost ferromagnetic system become magnetic rotons. Using self-consistent Hartree and renormalization group calculations, we study weak fluctuation-driven first-order quantum phase transitions, a quantum tricritical point controlled by anisotropy, and non-Fermi liquid behavior associated with the ...