Correlation Energy and the Spin Susceptibility of the Two-Valley Two-dimensional Electron Gas

TL;DR

This study uses advanced simulations to analyze the spin susceptibility of a two-valley 2D electron gas, revealing that weak disorder explains discrepancies with experimental results and providing a new analytical model.

Contribution

The paper introduces a new analytical expression for correlation energies in a two-valley 2D electron gas based on diffusion Monte Carlo simulations.

Findings

Spin susceptibility does not grow critically at low densities.

Weak disorder accounts for differences between theory and experiment.

Provides a local spin density functional for the system.

Abstract

We find that the spin susceptibility of a two-dimensional electron system with valley degeneracy does not grow critically at low densities, at variance with experimental results [A. Shashkin et al., Phys. Rev. Lett. 96, 036403 (2006)]. We ascribe this apparent discrepancy to the weak disorder present in experimental samples. Our prediction is obtained from accurate correlation energies computed with state of-the-art diffusion Monte Carlo simulations and fitted with an analytical expression which also provides a local spin density functional for the system under investigation.