Related papers: Stripe Structures and the Berry-Phase Connection: …
The spin-charge-orbital complex structures of manganites are studied using topological concepts. The key quantity is the "winding number" w associated with the Berry-phase connection of an e_g electron parallel-transported through…
The electronic structure of the zig-zag bilayer strip is analyzed. The electronic spectra of the bilayer strip is computed. The dependence of the edge state band flatness on the bilayer width is found. The density of states at the Fermi…
The electronic structure is found to be understandable in terms of free-atom term values and universal interorbital coupling parameters, since self-consistent tight-binding calculations indicate that Coulomb shifts of the d-state energies…
The effect of the Berry phase is included explicitly in the wavefunction describing conduction electrons in a crystal composed of periodically arrayed Jahn-Teller centers that have conically intersecting potential energy surfaces. The Berry…
Berry phase was originally defined for systems whose states are separated by finite energy gaps. One might naively expect that a system without a gap cannot have a Berry phase. Despite this we ask whether a Berry phase can be observed in a…
In correlated electron materials, electrons often self-organize and form a variety of patterns with potential ordering of charges, spins, and orbitals, which are believed to be closely connected to many novel properties of these materials…
We study the ground state structure of electronic-like bilayers, where different phases compete upon changing the inter-layer separation or particle density. New series representations with exceptional convergence properties are derived for…
The electronic structures of graphene systems and topological insulators have closely-related features, such as quantized Berry phase and zero-energy edge states. The reason for these analogies is that in both systems there are two relevant…
We study a two-dimensional charged particle interacting with a magnetic field, in general non-homogeneous, perpendicular to the plane, a confining potential, and a point interaction. If the latter moves adiabatically along a loop the state…
Based on the conventional energy band theory, an approach is presented to describe the electronic structure of crystalline insulators in the presence of a finite homogeneous electric field. The expression of polarization is derived which…
We investigate electronic transport in gapped bilayer graphene (gBLG) devices. For certain edge terminations -typically a combination of zigzag, armchair, and bearded types - we observe edge state conduction within the band gap, which is…
The selection rule on vibronic angular momentum of $t_{1u}^n \otimes h_g$ Jahn-Teller problem ($n = $ 1-5) is reinvestigated. It is shown that among three adiabatic orbitals only two have nonzero Berry phase. Thus, the Berry phase of…
Spin-charge-orbital ordered structures in doped layered manganites are investigated using an orbital-degenerate double-exchange model tightly coupled to Jahn-Teller distortions. In the ferromagnetic phase, unexpected diagonal stripes at…
We numerically investigate quantum rings in graphene and find that their electronic properties may be strongly influenced by the geometry, the edge symmetries and the structure of the corners. Energy spectra are calculated for different…
The Berry phase for a variety of systems comprising of two angular momenta is discussed. These include the electron and proton in the ground state of the hydrogen atom (taking into account the hyperfine interaction), the positronium atom,…
We investigate the possibility of a striped inhomoegenous phase occurring as an electronic system with an order parameter linearly coupled to the elastic degrees of freedom is tuned through the electronic phase transition. We find that in…
The Berry phase has found applications in building topological order parameters for certain condensed matter systems. The question whether some geometric phase for mixed states can serve the same purpose has been raised, and proposals are…
The electronic dispersion of a graphene bilayer is highly dependent on rotational mismatch between layers and can be further manipulated by electrical gating. This allows for an unprecedented control over electronic properties and opens up…
An explanation is given for the charge order, orbital order and insulating state observed in half-doped manganese oxides, such as Nd$_{1/2}$Sr$_{1/2}$MnO$_{3}$. The competition between the kinetic energy of the electrons and the magnetic…
The properties that quantify photonic topological insulators (PTIs), Berry phase, Berry connection, and Chern number, are typically obtained by making analogies between classical Maxwell's equations and the quantum mechanical…