Switchable transport properties of a two-dimensional electron gas based on ferroelectric Ca:SrTiO₃

Two-dimensional electron gases (2DEGs) obtained at surfaces and interfaces of oxides such as SrTiO₃ [1,2] form versatile platforms for nanoelectronics. Their gate-tunable carrier density, sheet resistance [3] and Rashba spin-orbit coupling [4] can be exploited for spin-orbitronics, as they promote highly efficient and electrically tunable spin-charge interconversion [5]. However, in most cases, the tunability of all these properties with an electric field remains volatile. In this talk we show the non-volatile modulation of the transport properties of a 2DEG, using the ferroelectricity of the Ca:SrTiO₃ host material [6,7]. Finally, we suggest that this behavior may be extended to other oxide 2DEGs, leading to novel types of electronic and spintronic architectures.

[1] A. Ohtomo and H. Y. Hwang, Nature 427, 423 (2004).
[2] T. C. Rödel et al., Advanced Materials 28, 1976 (2016).
[3] A. D. Caviglia et al., Nature 456, 624 (2008).
[4] A. D. Caviglia et al., Phys. Rev. Lett. 104, 126803 (2010).
[5] D. C. Vaz et al., Nat. Mater. 18, 1187 (2019).
[6] J. G. Bednorz and K. A. Müller, Phys. Rev. Lett. 52, 2289 (1984).
[7] J. Bréhin et al., Phys. Rev. Materials 4, 041002 (2020).