A few electrons per ion scenario for the B=0 metal-insulator transition in two dimensions

TL;DR

This paper proposes that the two-dimensional metal-insulator transition in systems like Si-MOSFETs is driven by a few strongly interacting electrons per ion, influencing scattering and transport properties.

Contribution

It introduces a novel scenario where a few electrons per ion dominate the transition, linking experimental observations with a new theoretical framework.

Findings

Transition likely due to few strongly interacting electrons

Electrons form bound pairs on the insulating side

Resistivity behavior linked to classical-quantum crossover

Abstract

We argue on the basis of experimental numbers that the B=0 metal-insulator transition in two dimensions, observed in Si-MOSFETs and in other two-dimensional systems, is likely to be due to a few strongly interacting electrons, which also interact strongly with the random positively ionized impurities. At the insulating side the electrons are all bound in pairs to the ions. On the metallic side free electrons exist which are scattered by ions dressed with electron-pairs and therefore alter the bare scattering potential of the ions. The physics at the metallic side of the transition is argued to be controlled by the classical to quantum transport cross-over leading to the observed non-monotonous dependence of the resistivity on temperature. This few electrons per ion scenario appears to be an experimentally realistic and testable scenario, which can also serve as a starting point for further theoretical analysis of the two-dimensional metal-insulator transition.