Electronic band reconstruction across the insulator-metal transition in colossal magnetoresistive EuCd2P2

TL;DR

This study uses angle-resolved photoemission to reveal electronic band reconstruction across the insulator-metal transition in EuCd2P2, linking magnetic order with electronic structure changes crucial for colossal magnetoresistance.

Contribution

It provides direct spectroscopic evidence of electronic band reconstruction associated with magnetic transition in EuCd2P2, advancing understanding of CMR mechanisms in Eu-based compounds.

Findings

Observation of magnetic band splitting during transition

Unusual energy shifts of valence bands detected

Link between Eu magnetic moment and electronic structure established

Abstract

While colossal magnetoresistance (CMR) in Eu-based compounds is often associated with strong spin-carrier interactions, the underlying reconstruction of the electronic bands is much less understood from spectroscopic experiments. Here using angle-resolved photoemission, we directly observe an electronic band reconstruction across the insulator-metal (and magnetic) transition in the recently discovered CMR compound EuCd2P2. This transition is manifested by a large magnetic band splitting associated with the magnetic order, as well as unusual energy shifts of the valence bands: both the large ordered moment of Eu and carrier localization in the paramagnetic phase are crucial. Our results provide spectroscopic evidence for an electronic structure reconstruction underlying the enormous CMR observed in EuCd2P2, which could be important for understanding Eu-based CMR materials, as well as designing CMR materials based on large-moment rare-earth magnets.