Effects of Particle-Hole Asymmetry on the Mott-Hubbard Metal-Insulator Transition

D. O. Demchenko, A. V. Joura, James K. Freericks

The Mott-Hubbard metal-insulator transition is one of the most important problems in correlated-electron systems. In the past decade, much progress has been made in examining a particle-hole symmetric form of the transition in the Hubbard model with dynamical mean field theory, where it was found that the electronic self-energy develops a pole at the transition. We examine the particle-hole asymmetric metal-insulator transition in the Falicov-Kimball model and find that a number of features change when the noninteracting density of states has a finite bandwidth.

Mateus Marques, Bruno Max de Souza Melo, Alexandre Reily Rocha +2 more

Arnab Banerjee, D. M. Silevitch, Alexander Palmer +2 more

David E. Logan, Martin R. Galpin

The paramagnetic phase of the one-band Hubbard model is studied at zero-temperature, within the framework of dynamical mean-field theory, and for general particle-hole asymmetry where a doping-induced Mott transition occurs. Our primary focus is the Mott insulator (MI) phase, and our main aim to establish what can be shown exactly about it. To handle the locally doubly-degenerate MI requires two distinct self-energies, which reflect the broken symmetry nature of the phase and together determine the standard single self-energy. Exact results are obtained for the local charge, local magnetic moment and associated spin susceptibilities, the interaction-renormalised levels, and the low-energy behaviour of the self-energy in the MI phase. The metallic phase is also considered briefly, and shown to acquire an emergent particle-hole symmetry as the Mott transition is approached. Throughout the metal, Luttinger's theorem is reflected in the vanishing of the Luttinger integral; for the generic MI by contrast this is shown to be non-vanishing, but again to have a universal magnitude. Numerical results are also obtained using NRG, for the metal/MI phase boundary, the scaling behaviour of the charge as the Mott transition is aproached from the metal, and associated universal scaling of single-particle dynamics as the low-energy Kondo scale vanishes.

Jun‐ichiro Kishine

We study the low-energy asymptotics of the $d=1+\ensuremath{\epsilon}$ dimensional Hubbard model with a circular Fermi surface where there is ${2k}_{F}$ umklapp scattering present a priori. Peculiarity of the $d=1+\ensuremath{\epsilon}$ dimensions is incorporated through the imbalance between the elementary particle-particle and particle-hole (PH) loops: infrared logarithmic singularity of the PH loop is smeared for $\ensuremath{\epsilon}>0.$ The one-loop renormalization-group flows indicate that a quantum phase transition from a metallic phase to the Mott insulator phase occurs at a finite on-site Coulomb repulsion U for $\ensuremath{\epsilon}>0.$ We also discuss effects of randomness.

R. Bulla, Thomas Pruschke, Alex C. Hewson