Do metals exist in two dimensions? A study of many-body localisation in low density electron gas

Abstract

Using a combination of ground state quantum Monte-Carlo and finite size scaling techniques, we perform a systematic study of the effect of Coulomb interaction on the localisation length of a disordered two-dimensional electron gas. We find that correlations delocalise the 2D system. In the absence of valley degeneracy (as in GaAs heterostructures), this delocalization effect corresponds to a finite increase of the localization length. The delocalisation is much more dramatic in the presence of valley degeneracy (as in Si MOSFETSs) where the localization length increases drastically. Our results suggest that a rather simple mechanism can account for the main features of the metallic behaviour observed in high mobility Si MOSFETs. Our findings support the claim that this behaviour is indeed a genuine effect of the presence of electron-electron interactions, yet that the system is not a ``true'' metal in the thermodynamic sense.

5 pages 4 figures

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Cited by in corpus (12)

• Dilute ferromagnetic semiconductors: Physics and spintronic structures
• Many-body localization transition in a lattice model of interacting fermions: statistics of renormalized hoppings in configuration space
• The energy scale behind the metallic behaviors in low-density Si-MOSFETs
• Metal-insulator transition and low-density phases in a strongly-interacting two-dimensional electron system
• Spin polarization and exchange-correlation effects in transport properties of two-dimensional electron systems in silicon
• Metallic state in a strongly interacting spinless two-valley electron system in two dimensions
• Spin effect on the low-temperature resistivity maximum in a strongly interacting 2D electron system
• Non-Gaussian Spatial Correlations Dramatically Weaken Localization
• Density wave propagation in a two-dimensional random dimer potential: from a single to a bipartite square lattice
• Statistical properties of two-particle transmission at Anderson transition
• Spin and valley effects on the quantum phase transition in two dimensions
• Anderson localization: a density matrix approach