Monolayers of 3He on the Surface of Bulk Superfluid 4He

TL;DR

This study investigates the two-dimensional fermion system formed by 3He monolayers on superfluid 4He surfaces, measuring interaction potentials, effective mass, and observing a second layer-state transition.

Contribution

It provides experimental measurements of 3He-3He interactions, effective mass, and confirms the existence of a second layer-state on superfluid 4He surfaces.

Findings

3He-3He potential V_3S/k_B = 0.23 K nm^2 (repulsive)

Effective mass m_3S ≈ 1.53 m_3

Observation of second layer-state at 0.6 monolayers

Abstract

We have used quantum evaporation to investigate the two-dimensional fermion system that forms at the free surface of (initially isotopically pure) 4He when small quantities of 3He are added to it. By measuring the first-arrival times of the evaporated atoms, we have determined that the 3He-3He potential in this system is V_3S/k_B=(0.23+/-0.02) K nm^2 (repulsive) and estimated a value of m_3S=(1.53+/-0.02)m_3 for the zero-coverage effective mass. We have also observed the predicted second layer-state which becomes occupied once the first layer-state density exceeds about 0.6 monolayers.