Self-doping instability of the Wigner-Mott insulator

Abstract

We present a theory describing the mechanism for the two-dimensional (2D) metal-insulator transition (MIT) in absence of disorder. A two-band Hubbard model is introduced, describing vacancy-interstitial pair excitations within the Wigner crystal. Kinetic energy gained by delocalizing such excitations is found to lead to an instability of the insulator to self-doping above a critical carrier concentration $n=n_c$, mapping the problem to a density-driven Mott MIT. This mechanism provides a natural microscopic picture of several puzzling experimental features, including the large effective mass enhancement, the large resistivity drop, and the large positive magneto-resistance on the metallic side of the transition. We also present a global phase diagram for the clean 2D electron gas as a function of $n$ and parallel magnetic field $B_{\parallel }$, which agrees well with experimental findings in ultra clean samples.

5 pages, 2 figures

References in corpus (8)

• Metal-insulator transition in two-dimensional electron systems
• Dilute electron gas near the metal-insulator transition in two dimensions
• The glass transition and the Coulomb gap in electron glasses
• Exchange Frequencies in the 2d Wigner crystal
• Mean field theory for the three-dimensional Coulomb glass
• Nonlinear screening theory of the Coulomb glass
• Effects of disorder on the non-zero temperature Mott Transition
• Linear temperature dependence of conductivity in Si two-dimensional electrons near the apparent metal-to-insulator transition

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• Doping driven metal-insulator transitions and charge orderings in the extended Hubbard model
• Emergent Heavy Fermion Behavior at the Wigner-Mott Transition
• Metal-insulator transition in the Hartree-Fock phase diagram of the fully polarized homogeneous electron gas in two dimensions
• Metal-insulator transition in the two-dimensional fully polarized homogeneous electron gas from Hartree-Fock solutions
• Quantum critical scaling for finite temperature Mott-like metal-insulator crossover in a few layered-MoS${}_2$
• Unconventional metallic conduction in two-dimensional Hubbard-Wigner lattices
• A metal-insulator transition in 2D: Established facts and open questions
• Exact solution of the 1D Hubbard model with NN and NNN interactions in the narrow-band limit
• Exact solution of the 1D Hubbard model in the atomic limit with inter-site magnetic coupling
• Polarization field in a single-valley strongly-interacting 2D electron system
• Particle-Hole Asymmetry and Pinball Liquid in a Triangular-Lattice Extended Hubbard Model within Mean-Field Approximation
• Electronic Crystal Phases in the Presence of Non-Uniform Berry Curvature and Tunable Berry Flux: The ${\lambda }_N$-Jellium model
• Defects in Wigner crystals: fracton-elasticity duality and vacancy proliferation