In collaboration with the National University of Singapore (NUS), researchers from the Laboratoire National des Champs Magnétiques Intenses (LNCMI) in Toulouse and the High Field Magnet Laboratory (HFML) in Dresden have investigated electronic subbands properties of the quasi-2DEG in a new 5d-oxide heterointerface, LaAlO/KTaO, via quantum oscillations in high magnetic fields. The high-mobility carriers at the interface were induced by implementing an ionic-liquid gating process at room temperature. In addition to the detailed information about the band structure of KTaO-2DEG, this study paves a way to create a high-mobility 2DEG based on other 5d oxides for which constructing an epitaxial heterointerface is almost impossible.

Figure – Quantum oscillations in the magnetoresistance of an ionic-liquid gated a-LaAlO/KTaO device measured down to 80 mK. The top inset includes an optical microscope image of a Hall bar patterned sample, a circuit diagram used for the ionic-liquid gating at room temperature and a schematic of gating process.

Publication – Electronic subbands in the a−LaAlO/KTaO interface revealed by quantum oscillations in high magnetic fields
K. Rubi, Shengwei Zeng, Femke Bangma, Michel Goiran, A. Ariando, Walter Escoffier, and Uli Zeitler
Physical Review Research 3, 033234 (2021).