We consider the problem of screening of an electrically charged impurity in a clean graphene sheet. When electron-electron interactions are neglected, the screening charge has a sign opposite to that of the impurity, and is localized near the impurity. Interactions between electrons smear out the induced charge density to give a largedistance tail that follows approximately, but not exactly, an...

We demonstrate analytically and numerically that the impurity mode plays a very important role in the kink scattering by a local inhomogeneity, and a sine-Gordon kink may be trapped by an impurity due to loss of its kinetic energy to excite the impurity mode. We develop a collective-coordinate approach to describe the kink—impurity interactions and calculate the threshold velocity ofkink captur...

The impurity transport simulation code TOTAL (TOroidal Transport Analysis Linkage) consisting of 1-D(dimensional) transport and 2or 3-D equilibrium is developed for analyzing tokamak and helical burning plasmas controlled by feedback scheme with gas puffing, pellet fueling injection and heating power modulations. In this code multi-species of impurity ions can be treated including neoclassical ...

We study a multichannel one-dimensional (1D) supersymmetric t−J model with an added magnetic impurity of arbitrary spin S. The antiferromagnetic impurity-electron interaction is chosen so as to preserve integrability, allowing for an exact diagonalization of the model by a Bethe Ansatz. The solution reveals that interactions in the bulk make the magnetic impurity drive both spin and charge fluc...

We study the localized magnetic states of an impurity in biased bilayer and trilayer graphene. It is found that the magnetic boundary for bilayer and trilayer graphene shows mixed features of Dirac and conventional fermions. For zero gate bias, as the impurity energy approaches the Dirac point, the impurity magnetization region diminishes for bilayer and trilayer graphene. When a gate bias is a...

In this paper we study an impurity in Bose-Einstein-Condensate system at T = 0K and suppose the contact forms for boson-boson and boson-impurity interactions. Using Bogoliubov theory and a further approximation corresponding to only think over the forward scattering of impurity by bosons, we derive a reduced Hamiltonian whose form is the same as the Fröhlich Hamiltonian for large polaron. By us...

We review the progress of nonmagnetic impurity doping studies on Fe-based superconductors. On the theoretical side, two highly promising candidates for the pairing symmetry order parameter, i.e. the multi-gap s++ and s± wave models, have been proposed but continuously debated. The debate arises because of the complex gap structure and exceptional magnetic and metallic behaviors of Fe-based supe...