Related papers: Magnetism and superconductivity in underscreened K…
We propose a possible realization of the overscreened Kondo impurity problem by a magnetic s=1/2 impurity embedded in a two-dimensional S=1 U(1) spin liquid with a Fermi surface. This problem contains an interesting interplay between…
Superconductivity and magnetism are usually the conflicting (competing) phenomena. We show, however, that in nanoscopic objects the electron pairing may promote the magnetic ordering. Such situation is possible at low temperatures in the…
The Kondo-lattice model describes a typical spin-charge coupled system in which localized spins and itinerant electrons are strongly coupled via exchange interactions and exhibits a variety of long-wavelength magnetic orders originating…
We investigate the entanglement properties of a Kondo system undergoing a transition to a state with a quenched magnetic impurity, using the density matrix renormalization group (DMRG) method. We focus on a two-channel spin-1 Kondo impurity…
We study the interplay of the Kondo effect and spin-polarized tunneling in a class of systems exhibiting uniaxial magnetic anisotropy, such as magnetic molecules, magnetic adatoms, or quantum dots coupled to a single localized magnetic…
Superconductors without inversion symmetry can exhibit a non-zero magnetization when a supercurrent is present, leading to non-dissipative magnetoelectric effects. Here, we focus on understanding the relation between the spin and orbital…
The quest for quantum ground states beyond the conventional Fermi-liquid paradigm remains a central challenge in many-body physics. The ferromagnetic Kondo effect represents a particularly intriguing case: an exotic variant of the Kondo…
Superconductivity in the cuprate oxide is studied by Kondo-lattice theory based on the t-J model with the el-ph interaction arising from the modulation of the superexchange interaction by phonons. The self-energy of electrons is decomposed…
We propose a mechanism of unconventional superconductivity in two-dimensional strongly-correlated electron systems. We consider a two-dimensional Kondo lattice system or double-exchange system with spin-orbit coupling arising from buckling…
We theoretically study the role of electron-electron interactions in one-dimensional magnetized helical states coupled to an s-wave superconductor. We consider a partially mixed helical (superhelical) regime, where the magnetic field…
We study the Kondo and transport properties of a quantum dot with a single magnetic Mn ion connected to metallic leads. By employing a numerical renormalization group technique we show that depending on the value of ferromagnetic coupling…
We summarize the present status of the theories of spin fluctuations in dealing with the anomalous or non-Fermi liquid behavior and unconventional superconductivity in strongly correlated electron systems around their magnetic instabilities…
Motivated by the recent finding of superconductivity in layered CoO_2 compounds, we investigate superconducting and magnetic instabilities of interacting electrons on the two-dimensional triangular lattice. Using a one-loop renormalization…
We study the low-temperature properties of the generalized Anderson impurity model in which two localized configurations, one with two doublets and the other with a triplet, are mixed by two degenerate conduction channels. By using the…
I apply a two-step renormalization group method to the study of the competition between antiferromagnetism (AFM) and superconductivity in an anisotropic 2D Hubbard model. I show that this simple model captures the essentials of the…
We study the behavior of magnetic superconductors which involve a local attractive interaction between electrons, and a coupling between local moments and the electrons. We solve this `Hubbard-Kondo' model through a variational minimization…
We consider the spatial spin correlations around a partially screened spin-1 magnetic moment in a metal exhibiting the underscreened Kondo effect. We find that the underscreening of the impurity spin results in spatial spin correlations…
We analyze the ground state properties of the two-dimensional quantum antiferromagnet with a S=1/2 Kondo impurity. Perturbation theory around the strong Kondo coupling limit is developed and the results compared with studies, based on exact…
The interplay between Kondo screening and magnetic order has long been a central issue in the physics of strongly correlated systems. While the Kondo effect has traditionally been understood to suppress magnetism through the formation of…
Strong correlation, when combined with dissipation in open systems, can lead to a variety of exotic quantum phenomena. Here, we study nontrivial interplays between non-Fermi liquid behaviors emerging from strong correlation and…