Related papers: Magnetic impurities in a charge-ordered background
We study the influence of spinless impurities on a frustrated magnet featuring a spin-density wave (stripe) phase by means of Monte Carlo simulations. We demonstrate that the interplay between the impurities and an order parameter that…
We explore the interplay of a charge density wave (CDW) order and s-wave superconductivity (sSC) in a disordered system. Recent experiments on 1T-TiSe_2, where the pristine sample has a commensurate CDW order and the superconductivity…
The thermal behavior of a one-dimensional antiferromagnetic chain doped by donor impurities was analyzed. The ground state of such a chain corresponds to the formation of a set of ferromagnetically correlated regions localized near…
The underdoped high-Tc materials are characterized by a competition between Cooper pairing and antiferromagnetic (AF) order. Important differences between the superconducting (SC) state of these materials and conventional superconductors…
We analyze the stability of excitonic ground states in the two-band Hubbard model with additional electron-phonon and Hund's rule couplings using a combination of mean-field and variational cluster approaches. We show that both the…
We consider an electron coupled to a random distribution of point vortices in the plane (magnetic impurities). We analyze the effect of the magnetic impurities on the density of states of the test particle, when the magnetic impurities have…
We have studied the critical temperature of Diluted Magnetic Semiconductors by means of Monte Carlo simulations and Coherent-Potential-Approximation (CPA) calculations. In our model for this syste m, the magnetic ions couple with the…
Non-local quasiparticles in correlated quantum materials can exhibit the proximity effect. For instance, in metal superconductor hybrid systems, the leaking of cooper pairs to the metallic region induces superconducting correlations in a…
We study the effect of quantum magnetic impurities on d-wave spin density waves (d-SDW). The impurity spins are aligned coherently according to the spin space anisotropy of the condensate. Both the order parameter and transition temperature…
In ordinary metals, antiferromagnetic exchange between conduction electrons and a magnetic impurity leads to screening of the impurity spin below the Kondo temperature, $T_K$. In systems such as semimetals, small-gap semiconductors and…
The appropriate generalization of the isotropic impurity Anderson model for valence fluctuations between two magnetic multiplets $l^n$ and $l^{n+1}$ is solved in the strong-coupling limit of Wilson's renormalization group for $l\leq$ 3.…
We consider the effects of local impurities in highly frustrated diamond lattice antiferromagnets, which exhibit large but non-extensive ground state degeneracies. Such models are appropriate to many A-site magnetic spinels. We argue very…
We discuss the interplay between electronic correlations and an underlying superlattice structure in determining the period of charge density waves (CDW's), by considering a one-dimensional Hubbard model with a repeated (non-random) pattern…
We study effects of an external magnetic field on charge ordering in the one-dimensional extended Hubbard model at quarter filling by means of the quantum Monte Carlo method. We find that the Zeeman coupling enhances the charge order…
Impurity pinning has long been discussed to have a profound effect on the dynamics of an incommensurate charge density wave (CDW), which would otherwise slide through the lattice without resistance. Here we visualize the impurity pinning…
Magnetic fields and magnetic impurities are each known to suppress superconductivity. However, as the field quenches (i.e. polarizes) the impurities, rich consequences, including field-enhanced superconductivity, can emerge when both…
The application of large magnetic fields ($B \sim B_{c2}$) to layered cuprates suppresses their high temperature superconducting behaviour and reveals competing ground states. In the widely-studied material YBa$_2$Cu$_3$O$_{6+x}$ (YBCO),…
We analyze charge order within the the spin-fermion model. We show that magnetically-mediated interaction gives rise to charge order $\Delta_k^Q = \langle c^\dagger_{{\bf k}+{\bf Q}} c_{{\bf k}-{\bf Q}}\rangle$ with momenta ${\bf Q}=Q_x…
Effects of nonmagnetic impurity doping on an AF spin-1/2 Heisenberg ladder system are studied by the QMC method. A single nonmagnetic impurity induces a localized spin-1/2 moment accompanied by "static" and enhanced AF correlations around…
We investigate the physics of a magnetic impurity with spin 1/2 in a correlated metallic host. Describing the band by a Hubbard Hamiltonian, the problem is analyzed using dynamical mean-field-theory in combination with Wilson's…