US-Aust Colloquium. Quantum Oscillations of Electrical Resistivity in an Insulator

Lu Li, Professor of Physics, University of Michigan

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Prof. Li will report on their result of the discovery of quantum oscillations in the electrical resistivity of a strongly correlated insulator and will bring crucial insight into understanding the ground state in gapped Kondo systems.

In metals, orbital motions of conduction electrons are quantized in magnetic fields, which is manifested by quantum oscillations in electrical resistivity. This Landau quantization is generally absent in insulators, in which all the electrons are localized. Here we report a notable exception in an insulator — ytterbium dodecaboride (YbB12). The resistivity of YbB12, despite much larger than that of usual metals, exhibits profound quantum oscillations under intense magnetic fields. This unconventional oscillation is shown to arise from the insulating bulk instead of conducting surface states. The large effective masses indicate strong correlation effects between electrons.

Prof. Lu’s research group investigates the novel magnetic and transport properties of strongly correlated systems, such as novel oxide interfaces, frustrated quantum magnets, and high Tc superconductors. In these systems, the strong correlation drives the interplay between various states of spins and orbitals and gives rise to an amazingly rich diversity of novel phenomena. The current research focus is the magnetism of the oxide interface LaAlO3/SrTiO3, LaNiO3/LaAlO3 and the electronic state of topological materials such as Cu(x)Bi2Se3 and the topological Kondo insulator SmB6 and YbB12.

This talk is part of an ongoing series of talks by US and Australian researchers presenting novel developments in condensed matter and cold atomic physics, enriching connections between the two physics communities. Co-presented by FLEET, Monash School of Physics and Astronomy, and the Joint Quantum Institute.

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