We discuss the interband light tunneling in a two-dimensional periodic photonic structure, as studied recently in experiments for optically induced photonic lattices [Trompeter, Phys. Rev. Lett. 96, 053903 (2006)]. We identify the Zener tunneling regime at the crossing of two Bloch bands, which occurs in the generic case of a Bragg reflection when the Bloch index crosses the edge of the irreduc...

We present an algorithm for the adaptive tetrahedral integration over the Brillouin zone of crystalline materials, and apply it to compute the optical conductivity, dc conductivity, and thermopower. For these quantities, whose contributions are often localized in small portions of the Brillouin zone, adaptive integration is especially relevant. Our implementation, thewoptic package, is tied int...

The present work reports a study of the structural, elastic, dynamical and thermodynamic properties of rock salt (RS) LiCl within density functional theory. It is found that the lattice constant and elastic constants are in very good agreement with the other calculations or experimental values. The phonon dispersion curve along several high symmetry lines at the Brillouin zone (BZ) is determine...

Angular resolved photoemission spectra of 5d core levels from Bi111 exhibit a component which is split off in energy by approximately 200 meV. The energy as well as the spectral width and relative intensity of the split off structure are strongly modulated by the final state electron momentum k(perpendicular) and k||, resembling the periodicity of the surface and bulk Brillouin zone. The data c...

We used a neutron spin-echo method with microelectron-volt resolution to determine the lifetimes of spin waves in the prototypical antiferromagnet MnF2 over the entire Brillouin zone. A theory based on the interaction of spin waves (magnons) with longitudinal spin fluctuations provides an excellent, parameter-free description of the data, except at the lowest momenta and temperatures. This is s...

we have calculated the phonon frequencies of kc1 along symmetry directions using an approach which is a combination of the frozen phonon and force constants methods. we also calculated griineisen parameters for all modes at x and l points in the brillouin zone. finally, the slope of acoustic dispersion curves around zone center were used to calculate the three independent elastic coefficients c...

We have calculated the phonon frequencies of KC1 along symmetry directions using an approach which is a combination of the frozen phonon and force constants methods. We also calculated Griineisen parameters for all modes at X and L points in the Brillouin zone. Finally, the slope of acoustic dispersion curves around zone center were used to calculate the three independent elastic coefficien...

An efficient, yet very accurate trial wave function, constructed from projecting the well-known Davydov D1 Ansatz onto momentum eigenstates, is employed to study the ground state properties of the generalized Holstein Hamiltonian with simultaneous diagonal and off-diagonal coupling. Ground-state energies have been obtained with a precision matching that of the computationally much more demandin...

A highly efficient extrapolative Brillouin-zone integration scheme is presented that requires a very low k-point sampling density for spectral integrations. It is important to use an extrapolative approach, since at low sampling densities interpolative schemes are hindered by problems associated with band crossing, which introduce spurious singularities in the density of states ~DOS!. The infor...