Related papers: Singular Effects of Impurities near the Ferromagne…
It is well-known that magnetic impurities can change the symmetry class of disordered metallic systems by breaking spin and time-reversal symmetry. At low temperature these symmetries can be restored by Kondo screening. It is also known…
Effect of randomness in the double-exchange model is studied. Large fluctuations and spatial random distribution of impurities are taken into account in an essentially exact manner by using the Monte Carlo calculation. The randomness…
The conductivity and the tunneling density of states of disordered itinerant electrons in the vicinity of a ferromagnetic transition at low temperature are discussed. Critical fluctuations lead to nonanalytic frequency and temperature…
In this letter, the Kondo magnetic effect is studied for the $XXZ$ spin chain where the impurities are coupled to the edges of the system. The Hamiltonian of our model can be constructed from the transfer matrix. It is exactly solvable and…
Quantum criticality describes the collective fluctuations of matter undergoing a second-order phase transition at zero temperature. Heavy fermion metals have in recent years emerged as prototypical systems to study quantum critical points.…
The problem of a spin-1/2 magnetic impurity near an antiferromagnetic transition of the host lattice is solved. The problem is shown to transform to a multichannel problem. A variety of fixed points is discovered asymptotically near the…
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…
We investigate the influence of an electromagnetic environment, characterized by a finite impedance $Z(\omega)$, on the Kondo effect in quantum dots. The circuit voltage fluctuations couple to charge fluctuations in the dot and influence…
We investigate theoretically the Seebeck effect in materials close to a ferromagnetic quantum critical point to explain anomalous behaviour at low temperatures. It is found that the main effect of spin fluctuations is to enhance the…
Motivated by recent experiments reporting superconductivity only at very low temperature in a class of heavy fermion compounds, we study the impact of energy fluctuations with small momentum transfer on the pairing instability near an…
Whether a small quantum mechanical system is able to equilibrate with its environment once an external local perturbation drives it out of thermal equilibrium is a central question which cuts across many different fields of science. Here we…
We consider magnetic impurities coupled to a conduction sea via a fully isotropic ferromagnetic spin-exchange term, the strength of which depends on the conduction-electron modes involved in the scattering. In the single-impurity case we…
Considerable evidence exists for the failure of the traditional theory of quantum critical points (QCPs), pointing to the need to incorporate novel excitations. The destruction of Kondo entanglement and the concomitant critical Kondo effect…
The breakdown of the Kondo effect may be the origin of the anomalous properties of the heavy-fermion compounds at low temperatures. We study the dynamics of one impurity embedded in an antiferromagnetic host at the quantum critical point…
We study the temperature dependence of the conductivity due to quantum interference processes for a two-dimensional disordered itinerant electron system close to a ferromagnetic quantum critical point. Near the quantum critical point, the…
Following the recent observation of the quantum spin Hall (QSH) effect in HgTe quantum wells, an important issue is to understand the effect of impurities on transport in the QSH regime. Using linear response and renormalization group…
Superconductivity mediated by spin fluctuations in weak and nearly ferromagnetic metals is studied close to the zero-temperature magnetic transition. We solve analytically the Eliashberg equations for p-wave pairing and obtain the normal…
A dilute concentration of magnetic impurities can dramatically affect the transport properties of an otherwise pure metal. This phenomenon, known as the Kondo effect, originates from the interactions of individual magnetic impurities with…
The variant of the single-impurity Kondo problem in which the conduction-band density of states has a power-law pseudogap at the Fermi energy is known to exhibit a zero-temperature phase transition at a finite exchange coupling. The…
We study the possibility to observe the two channel Kondo physics in multiple quantum dot heterostructures in the presence of magnetic field. We show that a fine tuning of the coupling parameters of the system and an external magnetic field…