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Now showing items 1-10 of 25

#### Electron-energy-loss and optical-transmittance investigation of Bi2Sr2CaCu2O8

(American Physical Society, 1990-07)

The energy-loss function Im(-1/ε) of Bi2Sr2CaCu2O8 has been measured over the range Eloss=0.8 to 80 eV by transmission electron-energy-loss spectroscopy (EELS) (nonimaging). The energy and momentum resolution were 0.1 eV ...

#### Critical dynamics at incommensurate phase transitions and NMR relaxation experiments

(American Physical Society, 1999-05)

We study the critical dynamics of crystals which undergo a second-order phase transition from a high-temperature normal phase to a structurally incommensurate (IC) modulated phase. We give a comprehensive description of ...

#### Continuum theory of vacancy-mediated diffusion

(American Physical Society, 1999-06)

We present and solve a continuum theory of vacancy-mediated diffusion (as evidenced, for example, in the vacancy driven motion of tracers in crystals). We restrict our attention to ultralow vacancy densities, so that a ...

#### Mobile spin bags and their interaction in the spin-density-wave background

(American Physical Society, 1990-02)

The motion of one doped hole in the spin-density-wave background has been studied by the variational approach. A spin-bag solution for the doped hole has been obtained that applies in the weak- and intermediate-coupling ...

#### Hole dynamics and effective hole-hole interaction in a quantum antiferromagnet

(American Physical Society, 1991-04)

By the use of an effective Hamiltonian which takes into account the constraint on the motion of holes in a quantum antiferromagnet, the dynamics of holes is investigated. It is found that there is a quasiparticle band whose ...

#### Solving the Ginzburg-Landau equations by finite-element methods

(American Physical Society, 1992-10)

We consider finite-element methods for the approximation of solutions of the Ginzburg-Landau equations of superconductivity. The methods are based on a discretization of the Euler-Lagrange equations resulting from the ...

#### Optical excitations in Bi2Sr2CuO6 and Bi2Sr2CaCu2O8: Evidence for localized (excitonic) and delocalized charge-transfer gaps

(American Physical Society, 1991-01)

The optical properties of Bi2Sr2CuO6 (2:2:0:1) and Bi2Sr2CaCu2O8 (2:2:1:2) have been investigated by transmission electron-energy-loss spectroscopy. At low energy, E(loss) less-than-or-equal-to 10.0 eV, common features are ...

#### Power spectrum of the current in systems with a conserved density

(American Physical Society, 1991-09)

Motivated by recent studies of model sandpiles, the power spectrum S of the current in dissipative dynamical systems with a conserved density is investigated. In contrast to self-organized criticality exhibited in certain ...

#### Finite-basis many-electron approximation to the Anderson model

(American Physical Society, 1990-03)

A relatively simple many-electron basis is used to construct a matrix for the Anderson impurity Hamiltonian. The basis states are each valid in the thermodynamic limit. The approximate ground-state energy compares well ...

#### New phase in the one-dimensional t-J model

(American Physical Society, 1993-05)

A new phase of a gas of pairs of electrons bounded in a singlet state is found in the one-dimensional t -J model for J > 2t and the density of electrons less than 0.2. This phase was conjectured in the study of the ...