# Magnetic 2D electron liquid at the surface of Heusler semiconductors

## TL;DR

This paper predicts the emergence of a rare magnetic and metallic surface state in certain Heusler semiconductors using first-principles calculations, revealing potential for high-temperature magnetic applications.

## Contribution

It is the first to theoretically demonstrate a non-magnetic semiconductor becoming magnetic and metallic at the surface in Heusler compounds.

## Key findings

- Magnetic surface states predicted in specific Heusler compounds.
- Magnetism in CoMnVAl persists above 155 K.
- Effective spin Hamiltonian parametrized for CoMnVAl.

## Abstract

Conducting and magnetic properties of a material often change in some confined geometries. However, a situation where a non-magnetic semiconductor becomes both metallic and magnetic at the surface is quite rare, and to the best of our knowledge has never been observed in experiment. In this work, we employ first-principles electronic structure theory to predict that such a peculiar magnetic state emerges in a family of quaternary Heusler compounds. We investigate magnetic and electronic properties of CoCrTiP, FeMnTiP and CoMnVAl. For the latter material, we also analyse the magnetic exchange interactions and use them for parametrizing an effective spin Hamiltonian. According to our results, magnetism in this material should persist at temperatures at least as high as 155 K.