Effects of Long-Range Correlations on Nonmagnetic Mott Transitions in Hubbard model on Square Lattice

Abstract

The mechanism of Mott transition in the Hubbard model on the square lattice is studied without explicit introduction of magnetic and superconducting correlations, using a variational Monte Carlo method. In the trial wave functions, we consider various types of binding factors between a doubly-occupied site (doublon, D) and an empty site (holon, H), like a long-range type as well as a conventional nearest-neighbor type, and add independent long-range D-D (H-H) factors. It is found that a wide choice of D-H binding factor leads to Mott transitions at critical values near the band width. We renew the D-H binding picture of Mott transitions by introducing two characteristic length scales, the D-H binding length l_{DH} and the minimum D-D distance l_{DD}, which we appropriately estimate. A Mott transition takes place at l_{DH}=l_{DD}. In the metallic regime (l_{DH}>l_{DD}), the domains of D-H pairs overlap with one another, thereby doublons and holons can move independently by exchanging the partners one after another. In contrast, the D-D factors give only a minor contribution to the Mott transition.

13 pages, 18 figures, submitted to J. Phys. Soc. Jpn

References in corpus (9)

• Many-Body Physics with Ultracold Gases
• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Monte Carlo study of two-dimensional Bose-Hubbard model
• Quantum Monte Carlo simulations of confined bosonic atoms in optical lattices
• Variational Monte Carlo Method Combined with Quantum-Number Projection and Multi-Variable Optimization
• Mott Transitions and d-wave Superconductivity in Half-Filled-Band Hubbard Model on Square Lattice with Geometric Frustration
• Superconductivity and a Mott Transition in a Hubbard Model on an Anisotropic Triangular Lattice
• Effect of Doublon-Holon Binding on Mott transition---Variational Monte Carlo Study of Two-Dimensional Bose Hubbard Models
• Variational Monte Carlo Study of Electron Differentiation around Mott Transition

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• Mixed singlet-triplet superconducting state within the moiré $t$-$J$-$U$ model as applied to the description of twisted WSe${}_2$ bilayer
• Correlated Band Structure of a Transition Metal Oxide ZnO Obtained from a Many-Body Wave Function Theory
• Staggered Flux State in Two-Dimensional Hubbard Models
• Charge dynamics of the antiferromagnetically ordered Mott insulator
• Assessing the orbital selective Mott transition with variational wave functions
• Drude and Superconducting Weights and Mott Transitions in Variation Theory
• Variational Monte Carlo Study of Spin-Gapped Normal State and BCS-BEC Crossover in Two-Dimensional Attractive Hubbard Model
• Doublon Dynamics of the Hubbard Model on Triangular Lattice
• Phase diagram of the Hubbard model on a square lattice: A cluster slave-spin study
• Excited States beyond Mott Gap in Half-Filled-Band Hubbard Model
• The odd-parity altermagnetism: A spin group study