We performed in-situ angle-resolved photoemission spectroscopy (ARPES) and spin-resolved ARPES (SARPES) experiments to investigate the relationship between electronic band structures and ferromagnetism in SrRuO3 (SRO) thin films. Our high-quality ARPES and SARPES results show clear spin-lifted band structures. The spin polarization is strongly dependent on momentum around the Fermi level, whereas it becomes less dependent at high-binding energies. This experimental observation matches our dynamical mean-field theory (DMFT) results very well. As temperature increases from low to the Curie temperature, spin-splitting gap decreases and band dispersions become incoherent. Based on the ARPES study and theoretical calculation results, we found that SRO possesses spin-dependent electron correlations in which majority and minority spins are localized and itinerant, respectively. Our finding explains how ferromagnetism and electronic structure are connected, which has been under debate for decades in SRO.
@article{arxiv.2111.07750,
title = {Observation of spin-dependent dual ferromagnetism in perovskite ruthenates},
author = {Sungsoo Hahn and Byungmin Sohn and Minjae Kim and Jeong Rae Kim and Soonsang Huh and Younsik Kim and Wonshik Kyung and Minsoo Kim and Donghan Kim and Youngdo Kim and Tae Won Noh and Ji Hoon Shim and Changyoung Kim},
journal= {arXiv preprint arXiv:2111.07750},
year = {2021}
}