## Search

Now showing items 31-40 of 78

#### 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 ...

#### Wulff shapes and the critical nucleus for a triangular Ising lattice

(American Physical Society, 2001-02)

Equilibrium Wulff shapes and interfacial energies of two-dimensional "crystals" on a triangular lattice are considered. Asymptotic approximations are constructed for both the shapes and energies in the limit T-->0 where ...

#### Effects of next-nearest-neighbor interactions on the orientation dependence of step stiffness: Reconciling theory with experiment for Cu(001)

(American Physical Society, 2004-12)

Within the solid-on-solid (SOS) approximation, we carry out a calculation of the orientational dependence of the step stiffness on a square lattice with nearest- and next-nearest-neighbor interactions. At low temperature ...

#### Transport in nanoscale conductors from first principles

(American Physical Society, 2002-01)

We describe a first-principles atomistic approach to calculate the electronic and atomic dynamics of nanoscale conductors under steady-state current flow. The approach is based on a self-consistent solution of the ...

#### 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 ...

#### Relevance of space anisotropy in the critical behavior of m-axial Lifshitz points

(American Physical Society, 2003-12)

The critical behavior of d-dimensional systems with n-component order parameter phi is studied at an m-axial Lifshitz point where a wave-vector instability occurs in an m-dimensional subspace R-m (m>1). Field theoretic ...

#### Koster-Slater model for the interface-state problem

(American Physical Society, 2000-10)

A Koster-Slater approach to the problem of localized states at semiconductor interfaces has been developed. It allows us to relate the existence and/or the energy position of interface states to some essential bulk features ...

#### 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 ...

#### Infrared activity in elemental crystals

(American Physical Society, 1994-03)

In a previous paper, Zallen [Phys. Rev. 173, 824 (1968)] reported a group-theoretical analysis of the competition between unit-cell complexity and crystal symmetry in determining the presence or absence of infrared-active ...