Related papers: Local Heavy Quasiparticle in Four-Level Kondo Mode…
We investigate the dependence of the ground state of a multi-level quantum dot on the coupling to an external fermionic system and on the interactions in the dot. As the coupling to the external system increases, the rearrangement of the…
The competition between the Kondo screening and indirect magnetic exchange in systems with two magnetic impurities coupled to a conventional s-wave superconductor gives rise to a nontrivial ground-state phase diagram. Here, we utilize the…
We have studied the interplay of an Anderson impurity in Landau quantized graphene, with special emphasis on the influence of the chemical potential. Within the slave-boson mean-field theory, we found reentrant Kondo behaviour by varying…
We present a general method to study weak-coupling instabilities of a large class of interacting electron models in a controlled and unbiased way. Quite generally, the electron gas is unstable towards a superconducting state even in the…
This is a popular review of some recent investigations of the Kondo effect in a variety of mesoscopic systems. After a brief introduction, experiments are described where a scanning tunneling microscope measures the surroundings of a…
We analyze the ground-state energy, local spin correlation, impurity spin polarization, impurity-induced magnetization, and corresponding zero-field susceptibilities of the symmetric single-impurity Kondo model on a tight-binding chain with…
We consider a Kondo impurity coupled to a fermionic host with a power-law density of states near the Fermi level, rho(epsilon) ~ |epsilon|^r, with exponent r<0. Using both perturbative renormalization group (poor man's scaling) and…
The numerical renormalization group is used to study quantum entanglement in the Kondo impurity model with a pseudogapped density of states $\rho(\varepsilon)\propto|\varepsilon|^r$ ($r>0$) that vanishes at the Fermi energy $\varepsilon=0$.…
A Kondo insulator (KI) is a prototypical example of a highly entangled phase of matter, where many-body interactions between local moments and delocalized electrons engender the non-magnetic insulating ground state. Conventionally, the…
We examine the low energy behavior of a double quantum dot in a regime where spin and pseudospin excitations are degenerate. The individual quantum dots are described by Anderson impurity models with an on-site interaction $U$ which are…
The anomalous low energy behaviour observed in metals with strong electron correlation, such as in the heavy fermion materials, is believed to arise from the scattering of the itinerant electrons with low energy spin fluctuations. In…
We extend the numerical renormalization-group method to treat Bose-Fermi Kondo models (BFKMs) describing a local moment coupled both to a conduction band and to a dissipative bosonic bath representing, e.g., lattice or spin collective…
We investigate the boundary phenomena that arise in a finite-size $XX$ spin chain interacting through an $XX$ interaction with a spin$-\frac{1}{2}$ impurity located at its edge. Upon Jordan-Wigner transformation, the model is described by a…
We study the competition between Kondo physics and dissipation within an Anderson model of a magnetic impurity level that hybridizes with a metallic host and is also coupled, via the impurity charge, to the displacement of a bosonic bath…
Quasiparticle interference has been used frequently for the purpose of unraveling the electronic states in the vicinity of the Fermi level as well as the nature of superconducting gap in the unconventional superconductors. Using the…
It is demonstrated theoretically that the circularly polarized irradiation of two-dimensional electron systems can induce the localized electron states which antiferromagnetically interact with conduction electrons, resulting in the Kondo…
Impurities coupled to superconductors offer a controlled platform to understand the interplay between superconductivity, many-body interactions, and non-equilibrium physics. In the equilibrium situation, local interactions at the impurity…
Proximity of two different materials leads to an intricate coupling of quasiparticles so that an unprecedented electronic state is often realized at the interface. Here, we demonstrate a resonance-type many-body ground state in graphene, a…
Both impurity- and magnetic-field-induced quasiparticle states in chiral $p$-wave superconductors are investigated theoretically by solving the Bogoliubov--de Gennes equations self-consistently. At the strong scattering limit, we find that…
Highly unconventional behavior of the thermodynamic response functions has been experimentally observed in a narrow gap semiconductor samarium hexaboride. Motivated by these observations, we use renormalization group technique to…