ELECTRONIC PHASES OF THE IONIC HUBBARD MODEL WITH COULOMB DISORDER
DOI:
https://doi.org/10.18173/2354-1059.2026-0018Keywords:
Metal–insulator transitions, ionic Hubbard model, Coulomb disorderAbstract
We investigate the effects of Coulomb disorder on the half-filled ionic Hubbard model within the framework of dynamical mean-field theory (DMFT), using the equation-of-motion method as the impurity solver, combined with typical medium theory (TMT). In contrast to conventional disordered Hubbard models, the ionic Hubbard model contains a staggered ionic potential that introduces additional competition between band-insulating and correlation-driven insulating tendencies. We analyze how this ionic potential modifies the electronic phases induced by Coulomb disorder through the arithmetic and geometric averages of the local density of states. In the absence of disorder, the system exhibits metallic (M), Mott-insulating (MI), and band-insulating (BI) phases. When Coulomb disorder is introduced, Anderson-insulating (AI) behavior and localized states (LS) inside the Mott gap are also observed. In particular, the LS regime appears between the metallic and Mott-insulating phases at small ionic potentials, whereas the AI regime develops for sufficiently large values of the Coulomb interaction and ionic potential. Our results show that the interplay between ionic potential, electron correlation, and disorder substantially influences the localization behavior and insulating characteristics of the ionic Hubbard model.
References
[1] N. F. Mott, “Electrons in disordered structures”, Advances in Physics, vol. 16, no. 61, pp. 49–144, 1967. http://dx.doi.org/10.1080/00018736700101265
[2] P. W. Anderson, “Absence of diffusion in certain random lattices”, Physical Review, vol. 109, no. 5, pp. 1492–1505, 1958. DOI: https://doi.org/10.1103/PhysRev.109.1492
[3] J. Hubbard and J. B. Torrance, “Model of the Neutral-Ionic Phase Transformation”, Physical Review Letters, vol. 47, no. 54, pp. 1747–1750, 1981. DOI: https://doi.org/10.1103/PhysRevLett.47.1750
[4] H. A. Tuan, “Metal–insulator transitions in the half-filled ionic Hubbard model”, Journal of Physics: Condensed Matter, vol. 22, no. 9, p. 095602, 2010. DOI: https://doi.org/10.1088/0953-8984/22/9/095602
[5] X. Zhuotao et al., “Quench dynamics in the one-dimensional mass-imbalanced ionic Hubbard model”, Physical Review B, vol. 107, no. 9, p. 195147, 2023. DOI: https://doi.org/10.1103/PhysRevB.107.195147
[6] O. A. Moreno Segura, K. Hallberg, A. A. Aligia, “Charge and spin gaps in the ionic Hubbard model with density-dependent hopping”, Physical Review B, vol. 108, no. 19, p. 195135, 2023. DOI: https://doi.org/10.1103/PhysRevB.108.195135
[7] N. T. H. Yen & H. A. Tuan, “Metal-insulator transitions in the two-dimensional ionic Hubbard model within coherent potential approximation”, Communications in Physics, vol. 36, no. 1, pp. 19–26, 2026. DOI: https://doi.org/10.15625/0868-3166/23350
[8] K. Byczuk, W. Hofstetter, D. Vollhardt, “Anderson localization vs. Mott Hubbard metal-insulator transition in disordered, interacting lattice fermion systems”, International Journal of Modern Physics B, vol. 24, no. 12–13, pp. 1727–1755, 2010. DOI: https://doi.org/10.1142/S0217979210064575
[9] M. C. O. Aguiar, V. Dobrosavljevic, E. Abrahams, G. Kotliar, “Critical Behavior at the Mott-Anderson Transition: A Typical-Medium Theory Perspective”, Physical Review Letters, vol. 102, no. 15, p. 156402, 2009. DOI: https://doi.org/10.1103/PhysRevLett.102.156402
[10] K. Byczuk et al., “Mott-Hubbard Transition versus Anderson Localization in Correlated Electron Systems with Disorder”, Physical Review Letters, vol. 94, no. 5, p. 056404, 2005. DOI: https://doi.org/10.1103/PhysRevLett.94.056404
[11] R. D. B. Carvalho, M. A. Gusmao, “Effects of band filling in the Anderson-Falicov-Kimball model”, Physical Review B, vol. 87, no. 8, p. 085122, 2013. DOI: https://doi.org/10.1103/PhysRevB.87.085122
[12] J. Park and E. Khatami, “Thermodynamics of the disordered Hubbard model studied via numerical linked-cluster expansions”, Physical Review B, vol. 104, no. 16, p. 165102, 2021. DOI: https://doi.org/10.1103/PhysRevB.104.165102
[13] W. Morong et al., “Disorder-controlled relaxation in a three-dimensional Hubbard model quantum simulator”, Physical Review Research, vol. 3, no. 1, L012009, 2021. DOI: https://doi.org/10.1103/PhysRevResearch.3.L012009
[14] K. W. Kim et al., “Metal-insulator transition in a disordered and correlated SrTi1-xRuxO3 system: Changes in transport properties, optical spectra, and electronic structure”, Physical Review B, vol. 71, no. 12, p. 125104, 2005. DOI: https://doi.org/10.1103/PhysRevB.71.125104
[15] A. Georges, G. Kotliar, W. Krauth and M. J. Rosenberg, “Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions”, Reviews of Modern Physics, vol. 68, no. 1, pp. 13–125, 1996. DOI: https://doi.org/10.1103/RevModPhys.68.13
[16] R. Bulla, A. C. Hewson and Th. Pruschke, “Numerical renormalization group calculations for the self-energy of the impurity Anderson model”, Journal of Physics: Condensed Matter, vol. 10, no. 37, pp. 8365–8380, 1998. DOI: https://doi.org/10.1088/0953-8984/10/37/02
[17] Y. Lu, M. W. Haverkort, “Exact diagonalization as an impurity solver in dynamical mean field theory”, The European Physical Journal Special Topics, vol. 226, no. 11–12, pp. 2549–2564, 2017. DOI: https://doi.org/10.1140/epjst/e2017-70042-4
[18] V. Dobrosavljevic et al., “Typical medium theory of Anderson localization: A local order parameter approach to strong-disorder effects”, Europhysics Letters, vol. 62, no. 1, pp. 76–82, 2003. DOI: https://doi.org/10.1209/epl/i2003-00364-5
[19] N. T. H. Yen, L. D. Anh & H. A. Tuan, “Anderson localization in the Anderson–Hubbard model with site-dependent interactions”, New Journal of Physics, vol. 24, no. 5, p. 053054, 2022. DOI: https://doi.org/10.1088/1367-2630/ac706e
