U(1) Slave-spin theory and its application to Mott transition in a multi-orbital model for iron pnictides

Abstract

A U(1) slave-spin representation is introduced for multi-orbital Hubbard models. As with the $Z_2$ form of L. de'Medici et al. (Phys. Rev. B 72, 205124 (2005)), this approach represents a physical electron operator as the product of a slave spin and an auxiliary fermion operator. For non-degenerate multi-orbital models, our U(1) approach is advantageous in that it captures the non-interacting limit at the mean-field level. For systems with either a single orbital or degenerate multiple orbitals, the U(1) and $Z_2$ slave-spin approachs yield the same results in the slave-spin-condensed phase. In general, the U(1) slave-spin approach contains a U(1) gauge redundancy, and properly describes a Mott insulating phase. We apply the U(1) slave-spin approach to study the metal-to-insulator transition in a five-orbital model for parent iron pnictides. We demonstrate a Mott transition as a function of the interactions in this model. The nature of the Mott insulating state is influenced by the interplay between the Hund's rule coupling and crystal field splittings. In the metallic phase, when the Hund's rule coupling is beyond a threshold, there is a crossover from a weakly correlated metal to a strongly correlated one, through which the quasiparticle speactral weight rapidly drops. The existence of such a strongly correlated metallic phase supports the incipient Mott picture of the parent iron pnictides. In the parameter regime for this phase and in the vicinity of the Mott transition, we find that an orbital selective Mott state has nearly as competitive a ground state energy.

7 pages, 2 figures

References in corpus (25)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Competing Orders and Spin-Density-Wave Instability in La(O${}_{1-x}$F${}_x$)FeAs
• Theory of Electron Nematic Order in LaOFeAs
• Origin of the ~150 K Anomaly in LaOFeAs; Competing Antiferromagnetic Superexchange Interactions, Frustration, and Structural Phase Transition
• Correlated electronic structure of LaOFeAs
• Ising and Spin orders in Iron-based Superconductors
• Fe-based high temperature superconductivity with Tc=31K bordering an insulating antiferromagnet in (Tl,K)FexSe2 Crystals
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• Bi-collinear antiferromagnetic order in the tetragonal $\alpha$-FeTe
• Origin of the spin density wave instability in AFe${}_2$As${}_2$ (A=Ba, Sr) as revealed by optical spectroscopy
• Orbital-Selective Mott transition out of band degeneracy lifting
• Orbital selective Mott transition in multi-band systems: slave-spin representation and dynamical mean-field theory
• Antiferromagnetic superexchange interactions in LaOFeAs
• Hund's coupling key role in multi-orbital correlations
• Iron pnictides as a new setting for quantum criticality
• Electronic Structure of the BaFe${}_2$As${}_2$ Family of Iron Pnictides
• Properties of a two orbital model for oxypnictide superconductors: Magnetic order, B_2g spin-singlet pairing channel, and its nodal structure
• Spin waves in the $(\pi ,0)$ magnetically ordered iron chalcogenide Fe${}_{1.05}$Te
• Mott transition in Modulated Lattices and Parent Insulator of (K,Tl)yFexSe2 Superconductors
• Theory for Superconductivity in Iron Pnictides at Large Coulomb U Limit
• Pnictides as frustrated quantum antiferromagnet close to a quantum phase transition
• Correlation effects in the iron pnictides

Cited by in corpus (46)

• Strong electronic correlations from Hund's coupling
• Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Rb) Superconductors
• Orbital-selective Mott Phase in Multiorbital Models for Alkaline Iron Selenides K(1-x)Fe(2-y)Se2
• Low-energy microscopic models for iron-based superconductors: a review
• Electron correlations and superconductivity in La${}_3$Ni${}_2$O${}_7$ under pressure tuning
• Orbital differentiation and the role of orbital ordering in the magnetic state of Fe superconductors
• Non-Fermi liquid behavior in a correlated flatband pyrochlore lattice
• Orbital-selective Mott phase in multiorbital models for iron pnictides and chalcogenides
• Interplay of nematic and magnetic orders in FeSe under pressure
• Is the orbital-selective Mott phase stable against interorbital hopping?
• Overview on the physics and materials of the new superconductor KxFe2-ySe2
• Interaction-resistant metals in multicomponent Fermi systems
• Emergent flat band and topological Kondo semimetal driven by orbital-selective correlations
• Electronic properties, correlated topology and Green's function zeros
• Quantum phase transition between orbital-selective Mott states in Hund's metals
• Accuracy of ghost-rotationally-invariant slave-boson and dynamical mean field theory as a function of the impurity-model bath size
• Analytical slave-spin mean-field approach to orbital selective Mott insulators
• Correlation, doping and interband effects on the optical conductivity of iron superconductors
• La${}_2$O${}_3$Fe${}_2$Se${}_2$, a Mott insulator on the brink of orbital-selective metalization
• Magnetic states of the five-orbital Hubbard model for one-dimensional iron-based superconductors
• Superconductivity in twisted WSe${}_2$ from topology-induced quantum fluctuations
• Orbital-dependent self-energy effects and consequences for the superconducting gap structure in multi-orbital correlated electron systems
• Alternative Kondo breakdown mechanism: Orbital-selective orthogonal metal transition
• Hund's metal crossover and superconductivity in the 111 family of iron-based superconductors
• Kondo effect and its destruction in hetero-bilayer transition metal dichalcogenides
• Accuracy of ghost-rotationally-invariant slave-boson theory for multiorbital Hubbard models and realistic materials
• Derivation of the Ghost Gutzwiller Approximation from Quantum Embedding principles: the Ghost Density Matrix Embedding Theory
• Electron correlations in the kagome flat band metal $\mathrm{CsC}{\mathrm{r}}_3\mathrm{S}{\mathrm{b}}_5$
• Electron correlations and $T$-breaking density wave order in a ${\mathbb{Z}}_2$ kagome metal
• Slave-spin mean field for broken-symmetry states: Néel antiferromagnetism and its phase separation in multi-orbital Hubbard models
• Phase diagram of the Hubbard model on a honeycomb lattice: A cluster slave-spin study
• Revisit of Antiferromagnetism in Hubbard Model by A Cluster Slave-Spin Method
• Dynamic charge Kondo effect and a slave fermion approach to the Mott transition
• Nematic spectral signatures of the Hund's metal
• Optical spectroscopy study of the collapsed tetragonal phase of CaFe${}_2$(As${}_{0.935}$P${}_{0.065}$)${}_2$ single crystals
• Theory of spin-excitation anisotropy in the nematic phase of FeSe obtained from RIXS measurements
• Spin dynamics in NaFeAs and NaFe${}_{0.53}$Cu${}_{0.47}$As probed by resonant inelastic X-ray scattering
• Phase diagram of the Hubbard model on a square lattice: A cluster slave-spin study
• Topological Kondo semimetals emulated in hetero-bilayer transition metal dichalcogenides
• The odd-parity altermagnetism: A spin group study
• Orbital-selective electron correlations in high-$T_{\mathrm{c}}$ bilayer nickelates: from a global phase diagram to implications for spectroscopy
• Mott transition, magnetic and orbital orders in the ground state of the two-band Hubbard model using variational slave-spin mean field formalism
• Eliminating Orbital Selectivity from the Metal-Insulator Transition by Strong Magnetic Fluctuations
• PhD Thesis: Electronic correlations in multiorbital systems
• Concealed Mott Criticality: Unifying the Kondo Breakdown and Doped Charge-Transfer Insulators
• Local-moment magnetism in Mn-based pnictides