Study of equilibrium carrier transfer in LaAlO&lt;sub&gt;3&lt;/sub&gt;/SrTiO&lt;sub&gt;3&lt;/sub&gt; from an epitaxial La&lt;sub&gt;1–&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;&lt;i&gt;Sr&lt;sub&gt;x&lt;/sub&gt;&lt;/i&gt;MnO&lt;sub&gt;3&lt;/sub&gt; ferromagnetic layer

Telesio, F.; Moroni, R.; Marré, D.; Vinai, G.; Panaccione, G.; Torelli, P.; Rusponi, S.; Piamonteze, C.; di Gennaro, E.; Khare, A.; Miletto Granozio, F.; Filippetti, A.

doi:10.1088/2399-6528/aaa943

Study of equilibrium carrier transfer in LaAlO₃/SrTiO₃ from an epitaxial La_1–xSr_xMnO₃ ferromagnetic layer

Telesio F, Moroni R, Marré D, Vinai G, Panaccione G, Torelli P, Rusponi S, Piamonteze C, di Gennaro E, Khare A, Miletto Granozio F & Filippetti A

Citation

Telesio, F., Moroni, R., Marré, D., Vinai, G., Panaccione, G., Torelli, P., … Filippetti, A. (2018). Study of equilibrium carrier transfer in LaAlO₃/SrTiO₃ from an epitaxial La_1–xSr_xMnO₃ ferromagnetic layer. Journal of Physics Communications, 2(2), 025010 (12 pp.). https://doi.org/10.1088/2399-6528/aaa943

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:4945

Using x-ray magnetic circular dichroism and ab-initio calculations, we explore the La_1–xSr_xMnO₃/LaAlO₃/SrTiO₃ (001) heterostructure as a mean to induce transfer of spin polarized carriers from ferromagnetic La_1–xSr_xMnO₃ layer into the 2DEG (two-dimensional electron gas) at the LaAlO₃/SrTiO₃ interface. By out-of-plane transport measurements, the tunneling across the LaAlO₃ barrier is also analyzed. Our results suggest small or vanishing spin-polarization for the 2DEG: magnetic dichroism does not reveal a neat signal on Ti atoms, while calculations predict, for the pristine stoichiometric interface, a small spin-resolved mobile charge of 2.5 x 10¹³ cm^–2 corresponding to a magnetic moment of 0.038 μ_B per Ti atom, tightly confined within the single SrTiO₃ layer adjacent to LaAlO₃. Such a small magnetization is hard to be detected experimentally and perhaps not robust enough to survive to structural disorder, native doping, or La_1–xSr_xMnO₃ dead-layer effects. Our analysis suggests that, while some spin-diffusion cannot be completely ruled out, the use of ferromagnetic La_1–xSr_xMnO₃ epilayers grown on-top of LaAlO₃/SrTiO₃ is not effective enough to induce robust spin-transport properties in the 2DEG. The examined heterostructure is nevertheless an excellent test-case to understand some fundamental aspects of the spin-polarized charge transfer in 2D wells.