Giant and Reversible Electronic Structure Evolution in a Magnetic Topological Material EuCd2As2

TL;DR

This study reveals a large, reversible change in the electronic structure of EuCd2As2 caused by doping, which also induces a magnetic transition, highlighting its potential for tunable topological and magnetic properties.

Contribution

It demonstrates a giant, reversible electronic structure evolution and doping-induced magnetic transition in EuCd2As2, providing a detailed phase diagram and new insights into magnetic topological materials.

Findings

Significant hole doping via surface absorption.

Dramatic electronic structure change with doping.

Doping-induced transition from antiferromagnetic to ferromagnetic state.

Abstract

The electronic structure and the physical properties of quantum materials can be significantly altered by charge carrier doping and magnetic state transition. Here we report a discovery of a giant and reversible electronic structure evolution with doping in a magnetic topological material. By performing high-resolution angle-resolved photoemission measurements on EuCd2As2,we found that a huge amount of hole doping can be introduced into the sample surface due to surface absorption. The electronic structure exhibits a dramatic change with the hole doping which can not be described by a rigid band shift. Prominent band splitting is observed at high doping which corresponds to a doping-induced magnetic transition at low temperature (below -15 K) from an antiferromagnetic state to a ferromagnetic state. These results have established a detailed electronic phase diagram of EuCd2As2 where the electronic structure and the magnetic structure change systematically and dramatically with the doping level. They further suggest that the transport, magnetic and topological properties of EuCd2As2 can be greatly modified by doping. These work will stimulate further investigations to explore for new phenomena and properties in doping this magnetic topological material.