CE-antiferromagnetic electronic structure in LaSr$_2$Mn$_2$O$_7$ revealed by micro-focused angle-resolved photoemission spectroscopy and tight-binding models

Abstract

We have investigated the electronic structure of LaSr$_2$Mn$_2$O$_7$ in the CE-type antiferromagnetic (CE-AFM) state below the Néel temperature using micro-focused angle-resolved photoemission spectroscopy ($μ$-ARPES) and tight-binding models. In agreement with the tight-binding calculations, we found a dispersive intensity around the X point in the $μ$-ARPES spectra, where the A-type antiferromagnetic (A-AFM) phase has no bands experimentally and theoretically, demonstrating that we have successfully captured the signatures of the CE-AFM band structure for the first time. Many observed features can be explained by the CE-AFM tight-binding bands, although some of them and the overall near-Fermi level intensity mapping can be explained by the A-AFM band structure. This indicates that the CE-AFM domain size would be no larger than the beam footprint size of a $\sim\!20$~{\textmu}m scale.