Spin-polarization transition in the two-dimensional electron gas

¹ INFM, Università di Roma "La Sapienza"- P.le Aldo Moro 2, 00185, Roma, Italy
² INFM, Dipartimento di Fisica Teorica, Università di Trieste Strada Costiera 11, 34014, Trieste, Italy

Received: 28 June 2000
Accepted: 22 November 2000

Abstract

We present a numerical study of magnetic phases of the 2D electron gas near freezing. The calculations are performed by diffusion Monte Carlo in the fixed-node approximation. At variance with the 3D case we find no evidence for the stability of a partially polarized phase. With plane wave nodes in the trial function, the polarization transition takes place at , whereas the best available estimates locate Wigner crystallization around . Using an improved nodal structure, featuring optimized backflow correlations, we confirm the existence of a stability range for the polarized phase, although somewhat shrunk, at densities achievable nowadays in 2-dimensional hole gases in semiconductor heterostructures. The spin susceptibility of the unpolarized phase at the magnetic transition is approximately 30 times the Pauli susceptibility.