Competition between excitonic charge and spin density waves: Influence of electron-phonon and Hund's rule couplings

Abstract

We analyze the stability of excitonic ground states in the two-band Hubbard model with additional electron-phonon and Hund's rule couplings using a combination of mean-field and variational cluster approaches. We show that both the interband Coulomb interaction and the electron-phonon interaction will cooperatively stabilize a charge density wave (CDW) state which typifies an "excitonic" CDW if predominantly triggered by the effective interorbital electron-hole attraction or a "phononic" CDW if mostly caused by the coupling to the lattice degrees of freedom. By contrast, the Hund's rule coupling promotes an excitonic spin density wave. We determine the transition between excitonic charge and spin density waves and comment on a fixation of the phase of the excitonic order parameter that would prevent the formation of a superfluid condensate of excitons. The implications for exciton condensation in several material classes with strongly correlated electrons are discussed.

8 pages, 6 figures

References in corpus (17)

• Evidence for an excitonic insulator phase in 1T-TiSe${}_2$
• Variational cluster approach to correlated electron systems in low dimensions
• Excitonic Bose-Einstein condensation in Ta2NiSe5 above room temperature
• Self-energy-functional approach: Analytical results and the Mott-Hubbard transition
• Variational cluster approach to spontaneous symmetry breaking: The itinerant antiferromagnet in two dimensions
• Spontaneous exciton condensation in 1T-TiSe2: a BCS-like approach
• On the possibility of an excitonic insulator at the semiconductor-semimetal transition
• Excitonic condensation in systems of strongly correlated electrons
• Bound state formation and nature of the excitonic insulator phase in the extended Falicov-Kimball model
• Spin excitations in the excitonic spin-density-wave state of the iron pnictides
• Impact of Electron-Hole Correlations on the 1T-TiSe2 Electronic Structure
• Hartree-Fock study of electronic ferroelectricity in the Falicov-Kimball model with $f$-$f$ hopping
• Fate of the excitonic insulator in the presence of phonons
• Charge-density wave induced by combined electron-electron and electron-phonon interactions in 1$T$-TiSe${}_2$: A variational Monte Carlo study
• Excitonic spin density wave state in iron pnictides
• Phase diagram of exciton condensate in doped two-band Hubbard model
• Spin-orbit-induced exotic insulators in a three-orbital Hubbard model with $(t_{2g}{)}^5$ electrons

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• Strong interband interaction in the excitonic insulator phase of Ta${}_2$NiSe${}_5$
• Photo-induced gap closure in an excitonic insulator
• Collective Modes in Excitonic Insulators: Effects of Electron-Phonon Coupling and Signatures in Optical Response
• Exciton-phonon cooperative mechanism of the triple-$q$ charge-density-wave and antiferroelectric electron polarization in TiSe${}_2$
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• Second order Josephson effect in excitonic insulators
• Signature of spin-triplet exciton condensations in LaCoO${}_3$ at ultrahigh magnetic fields up to 600 T
• Microscopic quantum interference in excitonic condensation of Ta${}_2$NiSe${}_5$
• A New Era of Excitonic Insulators
• Nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators
• Density waves in strongly correlated quantum chains
• LDA+DMFT approach to ordering phenomena and the structural stability of correlated materials
• Electric and magnetic multipoles and bond orders in excitonic insulators
• Low-energy excitation spectra in the excitonic phase of cobalt oxides
• Excitonic magnetism in $d^6$ perovskites
• Photoinduced electron-electron pairing in the extended Falicov-Kimball model
• Ultrafast charge carrier and exciton dynamics in an excitonic insulator probed by time-resolved photoemission spectroscopy
• Spontaneous Spin Textures in Multiorbital Mott Systems
• Excitonic Insulator State of the Extended Falicov-Kimball Model in the Cluster Dynamical Impurity Approximation
• Excitonic condensation reflecting electronic states in two-band Penrose-Hubbard model
• Excitonic magnet in external field: complex order parameter and spin currents
• Third-harmonic generation in excitonic insulators
• Theory of Orbital Susceptibility on Excitonic Insulator
• Excitonic insulator phase and dynamics of condensate in a topological one-dimensional model
• Spin texture and spin current in excitonic phases of the two-band Hubbard model
• Carrier-Density Control of the Quantum-Confined 1$T$-TiSe${}_2$ Charge-Density-Wave
• Excitonic Order and Superconductivity in the Two-Orbital Hubbard Model: Variational Cluster Approach
• A review on magnetic field induced spin crossover in LaCoO${}_3$ up to 600 T
• Effects of magnetic fields and orbital angular momentum on excitonic condensation in two-orbital Hubbard model
• Emergence of pure spin current in doped excitonic magnets
• Symmetry breaking states in the half-filled two-orbital Hubbard model with crystalline electric field
• Magnetic-field effect on excitonic condensation emergent in extended Falicov-Kimball model