325 research outputs found
Role of c-axis pairs in V2O3 from the band-structure point of view
The common interpretation of the LDA band structure of VO is that
the apparent splitting of the band into a low intensity structure deep
below the Fermi energy and a high intensity feature above it, is due to the
bonding-antibonding coupling of the vertical V-V pair. Using tight-binding
fitting to --as well as first-principles NMTO downfolding of-- the spin-up
LDA+U band, we show that there are other hopping integrals which are
equally important for the band shape as the integral for hopping between the
partners of the pair
Fermi pockets and correlation effects in underdoped YBa2Cu3O6.5
The detection of quantum oscillations in the electrical resistivity of
YBa2Cu3O6.5 provides direct evidence for the existence of Fermi surface pockets
in an underdoped cuprate. We present a theoretical study of the electronic
structure of YBa2Cu3O7-d (YBCO) aiming at establishing the nature of these
Fermi pockets, i.e. CuO2 plane versus CuO chain or BaO. We argue that electron
correlation effects, such as orbital-dependent band distortions and highly
anisotropic self-energy corrections, must be taken into account in order to
properly interpret the quantum oscillation experiments.Comment: A high-resolution version can be found at
http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/YBCO_OrthoII_LDA.pd
- …