N ov 2 01 8 Magnetoconductance at the 2 D MIT : Evidence for Micro-Emulsion Phases

Measurements of the in-plane magnetic field Bsat required to achieve full polarization of the electron spins in the strongly interacting two-dimensional electron system in a silicon MOSFET (Metal-Oxide-Semiconductor-Field-Effect Transistor) reveal the occurrence of a phase transition at a well-defined critical electron density for the metal-insulator transition determined from resistivity measurements. The behavior of Bsat as a function of electron density is consistent with the presence of the mixed electronic micro-emulsion phases proposed by Spivak and Kivelson [1].