2 research outputs found
Influence of anisotropic next-nearest-neighbor hopping on diagonal charge-striped phases
We consider the model of strongly-correlated system of electrons described by
an extended Falicov-Kimball Hamiltonian where the stability of some axial and
diagonal striped phases was proved. Introducing a next-nearest-neighbor
hopping, small enough not to destroy the striped structure, we examine
rigorously how the presence of the next-nearest-neighbor hopping anisotropy
reduces the -rotation degeneracy of the diagonal-striped phase. The
effect appears to be similar to that in the case of anisotropy of the
nearest-neighbor hopping: the stripes are oriented in the direction of the
weaker next-nearest-neighbor hopping.Comment: 9 pages, 3 figures, 1 tabl
Structural matters in HTSC; the origin and form of stripe organization and checker boarding
The paper deals with the controversial charge and spin self-organization
phenomena in the HTSC cuprates, of which neutron, X-ray, STM and ARPES
experiments give complementary, sometimes apparently contradictory glimpses.
The examination has been set in the context of the boson-fermion, negative-U
understanding of HTSC advocated over many years by the author. Stripe models
are developed which are 2q in nature and diagonal in form. For such a geometry
to be compatible with the data rests upon both the spin and charge arrays being
face-centred. Various special doping concentrations are closely looked at, in
particular p = 0.1836 or 9/49, which is associated with the maximization of the
superconducting condensation energy and the termination of the pseudogap
regime. The stripe models are dictated by real space organization of the holes,
whereas the dispersionless checkerboarding is interpreted in terms of
correlation driven collapse of normal Fermi surface behaviour and response
functions. The incommensurate spin diffraction below the resonance energy is
seen as in no way expressing spin-wave physics or Fermi surface nesting, but is
driven by charge and strain (Jahn-Teller) considerations, and it stands
virtually without dispersion. The apparent dispersion comes from the downward
dispersion of the resonance peak, and the growth of a further incoherent
commensurate peak ensuing from the falling level of charge stripe organization
under excitation.Comment: 49 pages with 8 figure