Alberto Nocera

Pairing tendencies in a two-orbital Hubbard model in one dimension

The recent discovery of superconductivity under high pressure in the ladder compound BaFe

Nonlocal correlations in the orbital selective Mott phase of a one-dimensional multiorbital Hubbard model

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Symmetry-conserving purification of quantum states within the density matrix renormalization group

S

Density matrix renormalization group study of a three-orbital Hubbard model with spin-orbit coupling in one dimension

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Signatures of Pairing in the Magnetic Excitation Spectrum of Strongly Correlated two-leg Ladders

has opened a new field of research in iron-based superconductors with focus on quasi one-dimensional geometries. In this publication, using the Density Matrix Renormalization Group technique, we study a two-orbital Hubbard model defined in one dimensional chains. Our main result is the presence of hole binding tendencies at intermediate Hubbard

Magnetic excitation spectra of strongly correlated quasi-one-dimensional systems: Heisenberg versus Hubbard-like behavior

U

Magnetic properties and pairing tendencies of the iron-based superconducting ladder BaFe2S3: Combined ab initio and density matrix renormalization group study

repulsion and robust Hund coupling

Unconventional fermionic pairing states in a monochromatically tilted optical lattice

J_H/U=0.25

Finite-temperature dynamics of the Mott insulating Hubbard chain

. Binding does not occur neither in weak coupling nor at very strong coupling. The pair-pair correlations that are dominant near half-filling, or of similar strength as the charge and spin correlation channels, involve hole-pair operators that are spin singlets, use nearest-neighbor sites, and employ different orbitals for each hole. The Hund coupling strength, presence of robust magnetic moments, and antiferromagnetic correlations among them are important for the binding tendencies found here.

Orbital and Charge Excitations as Fingerprints of an Orbital-Selective Mott Phase in the Block Magnetic State of BaFe

We study non-local correlations in a three-orbital Hubbard model defined on an extended one-dimensional chain using determinant quantum Monte Carlo and density matrix renormalization group methods. We focus on a parameter with robust Hunds coupling, which produces an orbital selective Mott phase (OSMP) at intermediate values of the Hubbard U, as well as an orbitally ordered ferromagnetic insulating state at stronger coupling. An examination of the orbital and spin-correlation functions indicates that the orbital ordering occurs before the onset of magnetic correlations in this parameter regime as a function of temperature. In the OSMP, we find that the self-energy for the itinerant electrons is momentum dependent, indicating a degree of non-local correlations while the localized electrons have largely momentum independent self-energies. These non-local correlations also produce relative shifts of the hole-like and electron-like bands within our model. The overall momentum dependence of these quantities is strongly suppressed in the orbitally-ordered insulating phase.