Bound states of 3He at the edge of a 4He drop on a cesium surface

TL;DR

This paper demonstrates that small amounts of 3He atoms in a 4He drop on cesium form localized bound states at the contact line, affecting the density distribution and surface coverage.

Contribution

It reveals the existence of edge-bound states of 3He in 4He drops on cesium, distinct from known surface states, and analyzes their structural properties.

Findings

3He atoms form bound states at the contact line of a 4He drop.

These edge states influence the density profile, spreading beyond the edge.

Large impurity numbers can coat the entire drop surface and isolate it from the substrate.

Abstract

We show that small amounts of 3He atoms, added to a 4He drop deposited on a flat cesium surface at zero temperature, populate bound states localized at the contact line. These edge states show up for drops large enough to develop well defined surface and bulk regions together with a contact line, and they are structurally different from the well-known Andreev states that appear at the free surface and at the liquid-solid interface of films. We illustrate the one-body density of 3He in a drop with 1000 4He atoms, and show that for sufficiently large number of impurities, the density profiles spread beyond the edge, coating both the curved drop surface and its flat base and eventually isolating it from the substrate.