SKM 2021 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 12: Focus Session: Spin-Charge Interconversion (joint session MA/HL)

HL 12.5: Invited Talk

Tuesday, September 28, 2021, 15:45–16:15, H5

Theory of spin and orbital Edelstein effects in a topological oxide two-dimensional electron gas — •Annika Johansson¹, Börge Göbel^1,2, Jürgen Henk¹, Manuel Bibes³, and Ingrid Mertig¹ — ¹Martin Luther University Halle-Wittenberg, Halle, Germany — ²Max Planck Institute of Microstructure Physics, Halle, Germany — ³Unité Mixte de Physique CNRS/Thales, Université Paris-Sud, Université Paris-Saclay, Palaiseau, France

SrTiO₃ (STO)-based two-dimensional electron gases (2DEGs) provide a highly efficient spin-to-charge conversion [1], also known as inverse Edelstein effect [2,3]. Recently, an extremely large spin-to-charge conversion efficiency was demonstrated in the 2DEG at the interface between STO and Al [4]. The application of a gate voltage leads to a strong variation and even sign changes of the spin-to-charge conversion.

We explain this unconventional gate dependence of the (inverse) spin Edelstein effect from a theoretical perspective by Boltzmann transport calculations within a multiorbital tight-binding model. Further, we report on the electrically induced magnetization originating from the orbital moments, known as orbital Edelstein effect [5]. At STO interfaces the orbital Edelstein effect exceeds the spin Edelstein effect by more than one order of magnitude.

[1] E. Lesne et al., Nat. Mater. 15, 1261 (2016)

[2] V. M. Edelstein, Solid State Commun., 73, 233 (1990)

[3] K. Shen et al., Phys. Rev. Lett. 112, 096601 (2014)

[4] D. Vaz et al., Nature Materials 18, 1187 (2019)

[5] A. Johansson et al., Phys. Rev. Research 3, 013275 (2021)