Multifunctional Oxide-2DEGS for Spin-Charge Interconversion

Spin-charge interconversion in systems with spin-orbit coupling offers a new path for the generation and detection of spin currents of great potential for application in spintronics. The Rashba-type spin-orbit coupling linked to the spatial inversion symmetry breaking appearing in the two-dimensional electron gases (2DEG) formed at the interface between LaAlO₃ and SrTiO₃ [1] or by deposition of Al, Ta or Y on SrTiO₃ [2, 3], Ca:SrTiO₃ [4] or KTaO₃ [5] allows for very efficient spin to charge interconversion [1, 2, 6]. Recently, possibilities to further enlarge or control the functionalities of oxide-2DEGs have emerged. One approach relies on making the 2DEG ferroelectric by exploiting the large electric-field- or Ca-doping-induced ferroelectric character in STO, while the other is by inducing spin polarization in the 2DEG by depositing a magnetic layer on top of the 2DEG. Combining both strategies, multiferroic 2DEGs have been realized, opening an avenue for ferroelectrically controllable chiral spin textures in 2DEGs and providing a new playground for non-volatile spin–orbitronics and non-reciprocal physics. We will review our efforts to obtain such multifunctional 2DEGs [7, 8, 9 , 10].

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