Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 101: Focus Session: SrTiO₃: A Versatile Material from Bulk Quantum Paraelectric to 2D Superconductor III (joint session TT/KFM/MA/O)

O 101.5: Vortrag

Freitag, 22. März 2024, 10:30–10:45, H 0104

Origin of spin-polarized 2DEG at the EuTiO₃(001) surface and LaAlO₃/EuTiO₃/SrTiO₃(001) interface — •Manish Verma and Rossitza Pentcheva — Department of Physics, Universität Duisburg-Essen

Since the discovery of a two-dimensional electron gas (2DEG) at the interface between the LaAlO₃ and SrTiO₃ band insulators, studies on oxide surfaces and interfaces uncovered an intriguing and rich physics, such as possible magnetism in 2DEG. Using density functional theory with an on-site Coulomb repulsion term U, we find a spin-polarized 2DEG at the EuTiO₃(001) surface arising from the interplay of ferromagnetic (FM) order of Eu-4f magnetic moments and the localization of electrons released from oxygen divacancies at the surface Ti sites, in agreement with in situ high-resolution angle-resolved photoemission [1]. The 2DEG at the LaAlO₃/EuTiO₃/SrTiO₃(001) interface is formed due to the polar discontinuity. The spin-polarization is due to the FM exchange interaction between Eu 4f and Ti 3d states and steers the occupation of d_xz/d_yz orbitals [2].

[1] R. Di Capua et al., Phys. Rev. Research 3 (2021) L042038

[2]. R. Di Capua et al., npj Quantum Mater. 7 (2022) 41

Keywords: Two-dimensional electron gas; defects