Observation of Spin-Dependent Dual Ferromagnetism in Perovskite Ruthenates

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 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 arc localized and itinerant, respectively. Our finding explains how ferromagnetism and electronic structure are connected, which has been under debate for decades in SRO.

Automated summary

In situ angle-resolved photoemission spectroscopy (ARPES) and spin-resolved ARPES (SARPES) experiments were conducted to investigate the relationship between electronic band structures and ferromagnetism in SrRuO3 (SRO) thin films. The results showed clear spin-lifted band structures with spin polarization strongly dependent on momentum. As temperature increased, the spin-splitting gap decreased and band dispersions became incoherent, indicating spin-dependent electron correlations in SRO. This finding helps to explain the connection between ferromagnetism and electronic structure in SRO, which has been debated for decades.