Orbital selective switching of ferromagnetism in an oxide quasi two-dimensional electron gas

Di Capua, R.; Verma, M.; Radovic, M.; Strocov, V.N.; Piamonteze, C.; Guedes, E.B.; Plumb, N.C.; Chen, Yu; D’Antuono, M.; De Luca, G.M.; Di Gennaro, E.; Stornaiuolo, D.; Preziosi, D.; Jouault, B.; Miletto Granozio, F.; Sambri, A.; Pentcheva, R.; Ghiringhelli, G.; Salluzzo, M.

doi:10.1038/s41535-022-00448-4

Orbital selective switching of ferromagnetism in an oxide quasi two-dimensional electron gas

Di Capua R, Verma M, Radovic M, Strocov VN, Piamonteze C, Guedes EB, Plumb NC, Chen Y, D’Antuono M, De Luca GM, Di Gennaro E, Stornaiuolo D, Preziosi D, Jouault B, Miletto Granozio F, Sambri A, Pentcheva R, Ghiringhelli G & Salluzzo M

Citation

Di Capua, R., Verma, M., Radovic, M., Strocov, V. N., Piamonteze, C., Guedes, E. B., … Salluzzo, M. (2022). Orbital selective switching of ferromagnetism in an oxide quasi two-dimensional electron gas. npj Quantum Materials, 7, 41 (10 pp.). https://doi.org/10.1038/s41535-022-00448-4

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:41524

Multi-orbital physics in quasi-two-dimensional electron gases (q2DEGs) triggers intriguing phenomena not observed in bulk materials, such as unconventional superconductivity and magnetism. Here, we investigate the mechanism of orbital selective switching of the spin-polarization in the oxide q2DEG formed at the (001) interface between the LaAlO₃, EuTiO₃ and SrTiO₃ band insulators. By using density functional theory calculations, transport, magnetic and x-ray spectroscopy measurements, we find that the filling of titanium-bands with 3d_xz/3d_yz orbital character in the EuTiO₃ layer and at the interface with SrTiO₃ induces an antiferromagnetic to ferromagnetic switching of the exchange interaction between Eu-4f⁷ magnetic moments. The results explain the observation of the carrier density-dependent ferromagnetic correlations and anomalous Hall effect in this q2DEG, and demonstrate how combined theoretical and experimental approaches can lead to a deeper understanding of emerging electronic phases and serve as a guide for the materials design of advanced electronic applications.