The variable range hopping theory, as formulated for exponentially localized impurity states, does not necessarily apply in the case of graphene with covalently attached impurities. We analyze the localization of impurity states in graphene using the nearest-neighbor, tight-binding model of an adatom-graphene system with Green's function perturbation methods. The amplitude of the impurity state...

We argue that the scanning tunneling microscope (STM) images of resonant states generated by doping Zn or Ni impurities into Cu-O planes of BSCCO are the result of quantum interference of the impurity signal coming from several distinct paths. The impurity image seen on the surface is greatly affected by interlayer tunneling matrix elements. We find that the optimal tunneling path between the S...

Imaging the magnetic fields around a non-magnetic impurity can provide a clear benchmark for quantifying the degree of magnetic frustration. Focusing on the strongly frustrated J1-J2 model and the spatially anisotropic J1a-J1b-J2 model, very distinct low energy behaviors reflect different levels of magnetic frustration. In the J1-J2 model, bound magnons appear trapped near the impurity in the g...

Zeeman splitting of the ground state of single impurities in the quantum wells of resonant tunneling heterostructures is reported. We determine the absolute magnitude of the effective magnetic spin splitting factor g∗ ⊥ for a single impurity in a 44 Å Al0.27Ga0.73As/GaAs/Al0.27Ga0.73As quantum well to be 0.28 ± 0.02. This system also allows for independent measurement of the electron tunneling ...

We consider a two-dimensional crystalline monolayer of carbon atoms with a single non-magnetic impurity. Using the Weyl Hamiltonian to describe electronic energy spectrum near the Dirac points, we calculate the wave function and energy of impurity states, as well as the induced magnetic moment associated with polarization of the electron system. We present a phase diagram of the localized magne...

It is shown that the confined impurity state of a semiconductor quantum well develops into an excited impurity band in the case of a superlattice. This is studied by following theoretically the transition from a single to a multiple quantum well or superlattice by exactly diagonalizing the three-dimensional Hamiltonian for a quantum well system with random impurities. Intersubband absorption ex...

Thermoelectric properties of silicene nanoribbons doped with magnetic impurity atoms are investigated theoretically for both antiparallel and parallel orientations of the edge magnetic moments. Spin density distribution and transport parameters have been determined by ab-initio numerical methods based on the density functional theory. Doping with magnetic atoms considerably modi es the spin den...

We theoretically investigate dc electron resonant tunneling through an impurity state in a quantum well assisted by hot acoustical phonons. Numerical results for the tunneling current, obtained by nonequilibrium Green functions, reflect the hot-phonon-induced change in the spectrum and population of the impurity state. The induced change of the I-V characteristics has a typical two-peak form, w...

A microscopic theory of the plasma resonance in layered metals is presented. It is shown that electron-impurity scattering can suppress the plasma resonance in the normal state and sharpen it in the superconducting state.

Interelectron interactions and correlations in quantum dots can lead to spontaneous symmetry breaking of the self-consistent mean field, resulting in the formation of Wigner molecules. With the use of spin-and-space unrestricted Hartree-Fock ~sS-UHF! calculations, such symmetry breaking is discussed for field-free conditions, as well as under the influence of an external magnetic field. Using a...