265 research outputs found
Spatial inhomogeneity and strong correlation physics: a dynamical mean field study of a model Mott-insulator/band-insulator heterostructure
We use the dynamical mean field method to investigate electronic properties
of heterostructures in which finite number of Mott-insulator layers are
embedded in a spatially infinite band-insulator. The evolution of the
correlation effects with the number of Mott insulating layers and with position
in the heterostructure is determined, and the optical conductivity is computed.
It is shown that the heterostructures are generally metallic, with moderately
renormalized bands of quasiparticles appearing at the interface between the
correlated and uncorrelated regions.Comment: 4 pages, 4 figure
Adaptively truncated Hilbert space based impurity solver for dynamical mean-field theory
We present an impurity solver based on adaptively truncated Hilbert spaces.
The solver is particularly suitable for dynamical mean-field theory in
circumstances where quantum Monte Carlo approaches are ineffective. It exploits
the sparsity structure of quantum impurity models, in which the interactions
couple only a small subset of the degrees of freedom. We further introduce an
adaptive truncation of the particle or hole excited spaces, which enables
computations of Green functions with an accuracy needed to avoid unphysical
(sign change of imaginary part) self-energies. The method is benchmarked on the
one-dimensional Hubbard model.Comment: 10 pages, 7 figure
Role of oxygen-oxygen hopping in the three-band copper-oxide model: quasiparticle weight, metal insulator and magnetic phase boundaries, gap values and optical conductivity
We investigate the effect of oxygen-oxygen hopping on the three-band
copper-oxide model relevant to high- cuprates, finding that the physics is
changed only slightly as the oxygen-oxygen hopping is varied. The location of
the metal-insulator phase boundary in the plane of interaction strength and
charge transfer energy shifts by eV or less along the charge transfer
axis, the quasiparticle weight has approximately the same magnitude and doping
dependence and the qualitative characteristics of the electron-doped and
hole-doped sides of the phase diagram do not change. The results confirm the
identification of LaCuO as a material with intermediate correlation
strength. However, the magnetic phase boundary as well as higher-energy
features of the optical spectrum are found to depend on the magnitude of the
oxygen-oxygen hopping. We compare our results to previously published one-band
and three-band model calculations.Comment: 13.5 pages, 16 figure
Transient trapping into metastable states in systems with competing orders
The quench dynamics of a system involving two competing orders is
investigated using a Ginzburg-Landau theory with relaxational dynamics. We
consider the scenario where a pump rapidly heats the system to a high
temperature, after which the system cools down to its equilibrium temperature.
We study the evolution of the order parameter amplitude and fluctuations in the
resulting time dependent free energy landscape. Exponentially growing thermal
fluctuations dominate the dynamics. The system typically evolves into the phase
associated with the faster-relaxing order parameter, even if it is not the
global free energy minimum. This theory offers a natural explanation for the
widespread experimental observation that metastable states may be induced by
laser induced collapse of a dominant equilibrium order parameter.Comment: 12 pages, 7 figure
- …