Studies on oxide quasi-two dimensional electron gas (q2DEG) have been a playground for the discovery of novel and sometimes unexpected phenomena, like the reported magnetism at the surface and at the interface between LaAlO3 and SrTiO3 non-magnetic materials. However, magnetism in this system is weak and there are evidences of a not intrinsic origin. Here, by using in-situ high-resolution angle resolved photoemission we demonstrate that ferromagnetic EuTiO3, the magnetic counterpart of SrTiO3 in the bulk, hosts a q2DEG at its (001) surface. This is confirmed by density functional theory calculations with Hubbard U terms in the presence of oxygen divacancies in various configurations, all of them leading to a spin-polarized q2DEG related to the ferromagnetic order of Eu-4f magnetic moments. The results suggest EuTiO3(001) as a new material platform for oxide q2DEGs, characterized by broken inversion and time reversal symmetries.
@article{arxiv.2003.05494,
title = {A two-dimensional electron gas at the (001) surface of ferromagnetic EuTiO$_{3}$(001)},
author = {R. Di Capua and M. Verma and M. Radovic and N. C. Plumb and J. H. Dil and Z. Ristic and E. B. Guedes and G. M. De Luca and D. Preziosi and Z. Wang and A. P. Weber and R. Pentcheva and M. Salluzzo},
journal= {arXiv preprint arXiv:2003.05494},
year = {2021}
}