Electronic band reconstruction across the insulator-metal transition in colossally magnetoresistive <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">EuCd</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">P</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
Huali Zhang, Feng Du, Xiaoying Zheng, Shuaishuai Luo, Yi Wu, H.Q. Zheng, Shengtao Cui, Zhe Sun, Zhengtai Liu, Dawei Shen, M. Smidman, Yu Song, M. Shi, Zhicheng Zhong, Chao Cao, Huiqiu Yuan, Yang Liu
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 ${\mathrm{EuCd}}_{2}{\mathrm{P}}_{2}$. 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 ${\mathrm{EuCd}}_{2}{\mathrm{P}}_{2}$, which could be important for understanding Eu-based CMR materials, as well as designing CMR materials based on large-moment rare-earth magnets.