Universality of Aperiodic Quantum Oscillations at Complex Oxide Interfaces

A two-dimensional electron gas (2DEG) has been observed at the interfaces and surfaces of various perovskite transition metal oxides, with notable examples being SrTiO₃ and KTaO₃. These 2DEGs have garnered significant attention due to their unique properties and potential applications. In particular, the coexistence of intriguing phenomena, such as spin-orbit interaction, magnetism, 2D superconductivity, and gate-tunable Fermi energy, gives these 2DEGs a multi-functional character holding promise for spintronics and quantum computing applications.
To unravel the electronic structure of the SrTiO₃- and KTaO₃-2DEG experimentally, I investigated quantum oscillations in magnetoresistance in various related interfaces in the extreme conditions of high magnetic fields (up to 60 Tesla) and low temperatures (down to 100 mK) [1-5]. The most exciting finding is that for all studied interfaces, the cyclotron mass and oscillation frequency increase with the magnetic field, indicating the presence of non-trivial electronic bands. In this talk, I will present novel insights into the electronic bands of the 2DEG based on perovskite oxides, achieved through a comprehensive analysis of quantum oscillations.
This work is done in collaboration with A. Ariando, Suvankar Chakraverty, Walter Escoffier, Uli Zeitler, Denis Candido, Mun Chan, and Neil Harrison.

References:
[1] K. Rubi et al., npj Quantum Materials 5, 1 (2020)
[2] K. Rubi et al., Physical Review Research 3, 033234 (2021).
[3] I. Leemarkers, K. Rubi et al., Journal of Physics: Condensed Matter 33, 465002 (2021).
[4] H. Yan, S. Zeng, K. Rubi et al., Advanced Materials Interfaces 9, 2201633 (2022).
[5] K. Rubi et al., arXiv:2307.04854 (2023).