Quantum Phase Transition in a Clean Two-Dimensional Electron System

TL;DR

This paper analyzes a quantum phase transition in a high-mobility silicon MOSFET using scaling theory, highlighting thermopower divergence and exploring its relation to Fermi liquid behavior.

Contribution

It provides a scaling analysis of the transition and predicts critical behavior of various observables, linking it to Fermi liquid to non-Fermi-liquid transition theories.

Findings

Thermopower diverges inversely linearly near the critical density.

Scaling theory predicts specific heat behavior at the transition.

Transition may represent a Fermi liquid to non-Fermi-liquid change.

Abstract

A quantum phase transition that was recently observed in a high-mobility silicon MOSFET is analyzed in terms of a scaling theory. The most striking characteristic of the transition is a divergence of the thermopower, according to an inverse linear law, as a critical value of the electron density is approached. A scaling description of this transition yields predictions about the critical behavior of other observables, e.g., the specific heat. We also explore the possibility that this transition realizes a recently predicted transition from a Fermi liquid to a non-Fermi-liquid state.