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

TL;DR

This paper demonstrates that resistivity near the 2D metal-insulator transition exhibits a universal scaling behavior driven by electron-electron interactions, supporting the Wigner-Mott transition framework.

Contribution

The study provides experimental evidence that electron-electron scattering governs transport near the 2D MIT, confirming the Wigner-Mott scaling in dilute electron gases.

Findings

Resistivity curves scale with a universal function of T/Tmax.

Max resistivity and Tmax follow power-law dependence on effective mass.

Electron-electron interactions dominate over disorder effects in transport.

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.