419 research outputs found
Superconducting properties of the hole-doped three-band \emph{d-p} model studied with minimal-size real-space \emph{d}-wave pairing operators
The three-band \emph{d-p} model is investigated by means of Variational
Monte-Carlo (VMC) method with the BCS-like wave-function supplemented by the
Gutzwiller and Jastrow correlators. The VMC optimization leads to -
superconducting state with a characteristic dome-like shape of the order
parameter for hole doping , in a good agreement with the
experimental observations. Also, the off-diagonal pair-pair correlation
functions, calculated within VMC, vindicates the results obtained very recently
within the diagrammatic expansion of the Gutzwiller wave function method
(DE-GWF) [cf. Phys. Rev. B \textbf{99}, 104511 (2019)]. Subsequently, the
nature of the - pairing is investigated by means of recently proposed
\emph{minimal-size real-space d-wave pairing operators} [Phys. Rev. B
\textbf{100}, 214502 (2019)]. An emergence of the long-range superconducting
ordering for both and orbitals is reported by analysing the
corresponding off-diagonal pair-pair correlation functions. The dominant
character of \emph{d-wave} pairing on orbitals is confirmed. Additionally,
the trial wave-function is used to investigate the magnetic properties of the
system. The analysis of spin-spin correlation functions is carried out and
shows antiferromagnetic , short-range order, as expected.
For the sake of completeness, the charge gap has been estimated, which for the
parent compound takes the value , and
agrees with values reported experimentally for the cuprates
Methods of risk analysis of telematic objels
The paper focuses on basic description of the tunnel as a telematic object and its architecture. Conventional
methods of risk analysis of telematic objects are introduced in relation to their safety. New approaches of risk quantification
are shown in connection to existing legislation and directives of European Commission
Field-induced Orbital Patterns in Ferromagnetic Layered Ruthenates
We study the evolution of orbital patterns in ferromagnetic layered
ruthenates due to the competition of Coulomb interactions, compressive c axis
and orthorhombic distortions in the presence of a polarizing orbital field
coupled to the angular momentum. By means of the exact diagonalization on a 2x2
cluster and a cluster embedded analysis where inter-plaquette interaction is
treated on mean field level, we determine the ground-state phase diagram.
Specifically, we demonstrate that, via the activation of two or three of t_2g
local orbital configurations, an external field applied along different
symmetry directions can lead to inequivalent orbital correlated states.
Starting from an antiferro-orbital pattern, for the easy axis case an orbital
ordered phase is induced, having strong next nearest neighbors ferro-orbital
correlations. Otherwise, a field applied along the hard axis leads a reduction
of local orbital moment in a way to suppress the orbital order.Comment: 11 page
- …