NMR measurements of a possible new quantum phase in 2D ³He

A monolayer of ³He adsorbed on graphite surface preplated with a monolayer of ⁴He constitutes an ideal model system for studying strongly correlated two-dimensional fermions. The system behaves as a fluid phase at low densities and as the density is increased, accompanied by a Mott localization, it approaches the 4/7 registered phase. Recent heat-capacity measurements suggest that before the Mott transition, there exists an intermediate hole-doped Mott localized phase. We started new NMR measurements focusing on this novel phase to verify its existence and characteristics. We measured the static magnetization of the system down to 10 mK as a function of density. The magnetization data continuously intervene the fluid phase and the 4/7 phase, and support the above mentioned scenario.