# Anomalous Quasiparticle Reflection from the Surface of a $^3$He-$^4$He Dilute Solution

## TL;DR

This study investigates how interactions between 3D and 2D $^3$He Fermi liquids at the surface of a dilute $^3$He-$^4$He mixture lead to anomalous quasiparticle reflection, affecting electron mobility on the surface.

## Contribution

It reveals a novel quasiparticle reflection mechanism caused by the interaction between 3D and 2D $^3$He Fermi liquids at the liquid surface.

## Key findings

- Observed anomalous enhancement of electron mobility.
- Attributed the enhancement to non-trivial quasiparticle reflection.
- Demonstrated interaction effects between 3D and 2D Fermi liquids.

## Abstract

A free surface of a dilute $^3$He-$^4$He liquid mixture is a unique system where two Fermi liquids with distinct dimensions coexist: a three-dimensional (3D) $^3$He Fermi liquid in bulk and a two-dimensional (2D) $^3$He Fermi liquid at the surface. To investigate a novel effect generated by the interaction between the two Fermi liquids, mobility of a Wigner crystal of electrons formed on the free surface of the mixture is studied. An anomalous enhancement of the mobility, compared with the case where the 3D and 2D systems do not interact with each other, is observed. The enhancement is explained by non-trivial reflection of 3D quasiparticles from the surface covered with the 2D $^3$He system.