Revealing unconventional quantum oscillations in the two- dimensional electron gas at complex oxide interfaces

by Dr. Km Rubi (National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, USA)

Monday, March 20, 2023 from 14:30 to 15:30 (Asia/Kolkata)
at AG 80 https://zoom.us/j/94805584304?pwd=bmc5OW5TQVQxMXNyUHk2WUxUZWZHQT09 Meeting ID: 948 0558 4304 Passcode: 014595

Description

Two-dimensional electron gas (2DEG) has been discovered at the surface and interface of many perovskite transition metal oxides. The well-known and most widely studied oxides- based 2DEG exists at the interface between LaAlO3 (LAO) and SrTiO3 (STO). At this interface, the coexistence of multiple intriguing phenomena (e.g., giant magnetoresistance, spin-orbit interaction, magnetism, and 2D superconductivity) makes it promising for many applications, including spintronics and quantum computing. However, the key to the success of this interface for technological applications lies in understanding its electronic properties. 
To experimentally examine the electronic band properties of 2DEG at the LAO/STO interface as well as other oxides-based 2DEG, I measured the Shubnikov-de Haas effect (quantum oscillations in magnetoresistance) in LAO/STO [1, 2], LAO/KTaO3 (KTO) [3, 4], and EuO/KTO in the extreme environment of high magnetic fields (up to 60 Tesla) and low temperatures (down to 0.1 K). Interestingly, unlike the simple cases in which quantum oscillations are periodic in the inverse magnetic field, I observed a progressive magnetic field-dependent variation in oscillations’ frequency of oxides-based 2DEG. In this talk, I will present techniques I used to measure the Shubnikov-de Haas effect in both high continuous and pulsed magnetic fields. Further, by presenting a detailed analysis of unconventional quantum oscillations in LAO/STO and EuO/KTO, I will reveal a new insight into the electronic band structure of oxides-based 2DEG, one of the plausible candidates for next-generation electronics, spintronics, and quantum computing/information.
 
References: 
[1] K. Rubi, J. Gosteau, R. Serra, et al., Nature npj Quantum Materials, 5, 9 (2020).
[2] I. Leermakers, K. Rubi, M. Yang, et al., Journal of Physics: Condensed Matter, 33, 465002 (2021). [3] K. Rubi, S. Zeng, F. Bangma, et al., Physical Review Research, 3, 033234 (2021).
[4] H. Yan, S. Zeng, K. Rubi et al., Advanced Materials Interfaces, 9, 2201633 (2022).