Most d(0) transition metal (TM) oxides exhibit anomalously large Born dynamical charges associated with off-centering or motion of atoms along the TM-O chains. To understand their chemical origin, we introduce "Wannier orbital overlap population" (WOOP) and "Wannier orbital position population" (WOPP) in terms of the Wannier function based description of electronic structure obtained within fir...

We have adapted the maximally localized Wannier function approach of Souza et al (2002 Phys. Rev. B 65 035109) to the density functional theory based SIESTA code (Soler et al 2002 J. Phys.: Condens. Mater. 14 2745) and applied it to the study of Co substitutional impurities in bulk copper as well as to the Cu(111) surface. In the Co impurity case, we have reduced the problem to the Co d-electro...

The extended Wannier model describes the propagation of two-electron wave packet along the Wannier ridge from the reaction zone (where it is formed by (y, 2e) or (e, 2e) process) to the zone of free electron motion. The angular correlation patterns are calculated and analyzed for lSe and IPo states of the two-electron continuum.

We present a new scheme to include the van der Waals (vdW) interactions in approximated Density Functional Theory (DFT) by combining the quantum harmonic oscillator model with the maximally localized Wannier function technique. With respect to the recently developed DFT/vdW-WF2 method, also based on Wannier Functions, the new approach is more general, being no longer restricted to the case of w...

We report an experimental study of the Wannier-Stark fan and the fractional Wannier-Stark ladder using laser-cooled sodium atoms in an accelerating one-dimensional standing wave of light. We prepare the atoms in the lowest motional band of the optical lattice and then impose a constant acceleration. A weak oscillatory component is added to the acceleration in order to resonantly drive interband...

In this work, we use Wannier functions to analyze topological phase transitions in one-dimensional photonic crystals. We first review the construction of exponentially localized one dimension, and show how numerically construct them for systems. then apply these tools study a analog Su-Schrieffer-Heeger model. quantitatively accurate approximate model transition, compute localization defect sta...

Microscopic mechanisms of the puzzling insulating ferromagnetism of half-filled La4Ba2Cu2O10 are elucidated with energy-resolved Wannier states. The dominant magnetic coupling, revealed through evaluated parameters (t, U, and J), turns out to be the intersite direct exchange, a currently ignored mechanism that overwhelms the antiferromagnetic superexchange. By contrast, the isostructural Nd4Ba2...

Using the basis of Wannier states, we study the local dynamics of polarization gradient cooling for an atom driven on a Jg52→Je53 transition by a one-dimensional optical lattice. This analysis allows us to formulate a physical picture of the cooling mechanism, analogous to Sisyphus cooling for a Jg51/2→Je53/2 atom, which depends strongly on coherences in the Zeeman sublevels of the ground state...