Orbital‐selective Mott transitions in the 2‐band Jz‐model: a high‐precision quantum Monte Carlo study

Dongen, P. G. J. van; Knecht, C.; Blümer, N.

doi:10.1002/pssb.200562449

Cited by 11 publications

(5 citation statements)

References 18 publications

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“…Each of these bands is characterized by a local potential plus various Hund rule couplings (which can also couple inequivalent bands). Thus, the multi-orbital case is not only richer physically [14][15][16][17][18] (including the possibility of orbital-selective Mott transitions [19][20][21][22][23] ), but is complex already by the number of parameters. In addition, obtaining accurate numerical results rapidly becomes costly and challenging with increasing number M of orbitals.…”

Section: Introductionmentioning

confidence: 99%

Mott transitions in the half-filled SU(2M) symmetric Hubbard model

Blümer

Gorelik

2013

Phys. Rev. B

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The Hubbard model with large orbital degeneracy has recently gained relevance in the context of ultracold earth alkali like atoms. We compute its static properties in the SU(2M) symmetric limit for up to M=8 bands at half filling within dynamical mean-field theory, using the numerically exact multigrid Hirsch-Fye quantum Monte Carlo approach. Based on this unbiased data, we establish scaling laws which predict the phase boundaries of the paramagnetic Mott metal-insulator transition at arbitrary orbital degeneracy M with high accuracy.Comment: 10 pages, 10 figures; version to appear in PRB (minor corrections, ref. added

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Section: Introductionmentioning

confidence: 99%

Mott transitions in the half-filled SU(2M) symmetric Hubbard model

Blümer

Gorelik

2013

Phys. Rev. B

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“…[12][13][14][15][16][17][18][19][20][21][22][23][24] The early DMFT studies on this problem are focused on the twoband Hubbard model with half filling, which is the simplest system that may have OSMT when the bandwidths of the two bands are different. The DMFT calculations from different groups with exact diagonalization (ED) 12,13 and Hirsch-Fye quantum Monte Carlo (HFQMC) [14][15][16][17][18] as impurity solvers converge to two essential conclusions: (1) The OSMT in two-band Hubbard model is mainly induced by the bandwidth difference which breaks the degeneracy between the two bands and the crystal field splitting plays a minor role here. (2) The emergence of OSMT is very sensitive to the feature of the local interaction.…”

Section: Introductionmentioning

confidence: 99%

Complete phase diagram for three-band Hubbard model with orbital degeneracy lifted by crystal field splitting

Dai

2012

Phys. Rev. B

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Motivated by the unexplored complexity of the phase diagrams for multi-orbital Hubbard models, a three-band Hubbard model at integer fillings (N = 4) with orbital degeneracy lifted partially by crystal field splitting is analyzed systematically in this work. By using single site dynamical meanfield theory and rotationally invariant Gutzwiller approximation, we have computed the full phase diagram with Coulomb interaction strength U and crystal field splitting ∆. We find a large region in the phase diagram, where an orbital selective Mott phase will be stabilized by the positive crystal field lifting the orbital degeneracy. Further analysis indicates that the Hund's rule coupling is essential for the orbital selective Mott phase and the transition toward this phase is accompanied by a high-spin to low-spin transition. Such a model may be relevant for the recently discovered pnictides and ruthenates correlated materials.

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“…The expectation that this "standard model" for OSMTs captures the essence of the phenomenon, i.e., resolves two distinct orbital-selective transitions at half filling and low temperatures, could indeed be verified, 23 after some initial confusion. 24 In accordance with previous literature, 25,26 we will refer to this model as the "J z -model". The general doped case was investigated in detail in Ref.…”

Section: 16mentioning

confidence: 82%

Orbital-selective Mott transitions in a doped two-band Hubbard model with crystal field splitting

2013

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We investigate the effects of crystal field splitting in a doped two-band Hubbard model with different bandwidths within dynamical mean-field theory (DMFT), using a quantum Monte Carlo impurity solver. In addition to an orbital-selective Mott phase (OSMP) of the narrow band, which is adiabatically connected with the well-studied OSMP in the half-filled case without crystal field splitting, we find, for sufficiently strong interaction and a suitable crystal field, also an OSMP of the wide band. We establish the phase diagram (in the absence of magnetic or orbital order) at moderate doping as a function of interaction strength and crystal field splitting and show that also the wide-band OSMP is associated with non-Fermi-liquid behavior in the case of Ising type Hund rule couplings. Our numerical results are supplemented by analytical strong-coupling studies of spin order and spectral functions at integer filling.

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Orbital‐selective Mott transitions in the 2‐band J_z‐model: a high‐precision quantum Monte Carlo study

Cited by 11 publications

References 18 publications

Mott transitions in the half-filled SU(2M) symmetric Hubbard model

Mott transitions in the half-filled SU(2M) symmetric Hubbard model

Complete phase diagram for three-band Hubbard model with orbital degeneracy lifted by crystal field splitting

Orbital-selective Mott transitions in a doped two-band Hubbard model with crystal field splitting

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