Novel 2D electron gases at the surface of transition-metal oxides

DIPC Seminars

Andrés F. Santander-Syro (CSNSM – Université Paris-Sud, France)
Donostia International Physics Center
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Novel 2D electron gases at the surface of transition-metal oxides **Novel 2D electron gases at the surface of transition-metal oxides** ** ** Andrés F. Santander-Syro CSNSM – Université Paris-Sud (France) Transition-metal oxides (MOs) show remarkable properties, such as high- temperature superconductivity or large magnetoresistance. The realization of two-dimensional electron gases (2DEGs) at surfaces or interfaces of TMOs, a field of current intense research, is crucial for harnessing the functionalities of these materials for future applications. Additionally, these 2DEGs offer the possibility to explore new physics emerging from the combined effects of electron correlations and low-dimensional confinement. Recently, we discovered that 2DEGs can be simply realized at the surface of various insulating transparent TMOs, such as the quantum paraelectric SrTiO3 [1] or the strong spin-orbit coupled KTaO3 [2]. In this talk, I will show that by choosing various surface terminations one can additionally tailor the electronic structure and symmetries of these 2DEGs [3-4], paving the way for the quest of topological states in correlated oxides. Furthermore, I will discuss our latest observation of a giant spin splitting, of 100 meV, of bands with opposite spin chiralities in the 2DEG at the surface of SrTiO3 [5]. These results show that confined electronic states at oxide surfaces can be endowed with novel properties, not present in the bulk, which are promising for technological applications. [1] A. F. Santander-Syro _et al_., Nature **469** , 189 (2011). [2] A. F. Santander-Syro _et al_., Phys. Rev. B **86** , 121107(R) (2012). [3] C. Bareille _et al_., Sci. Rep. **4** , 3586 (2014). [4] T. C. Rödel _et al_., Phys. Rev. Applied **1** , 051002 (2014). [5] A. F. Santander-Syro _et al_ , Nature Mater. **13** , 1085 (2014).