Wigner-Mott scaling of transport near the two-dimensional metal-insulator transition

Abstract

Electron-electron scattering usually dominates the transport in strongly correlated materials. It typically leads to pronounced resistivity maxima in the incoherent regime around the coherence temperature \(T^{*}\), reflecting the tendency of carriers to undergo Mott localization following the demise of the Fermi liquid. This behavior is best pronounced in the vicinity of interaction-driven (Mott-like) metal-insulator transitions, where the \(T^{*}\) decreases, while the resistivity maximum \(\rho_{max}\) increases. Here we show that, in this regime, the entire family of resistivity curves displays a characteristic scaling behavior \(\rho(T)/\rho_{max}\approx F(T/T_{max}),\) while the \(\rho_{max}\) and \(T_{max}\sim T^{*}\) assume a powerlaw dependence on the quasi-particle effective mass \(m^{*}\). Remarkably, precisely such trends are found from an appropriate scaling analysis of experimental data obtained from diluted two-dimensional electron gases in zero magnetic fields. Our analysis provides strong evidence that inelastic electron-electron scattering -- and not disorder effects -- dominates finite temperature transport in these systems, validating the Wigner-Mott picture of the two-dimensional metal-insulator transition.