Affiliation
TU Wien
Title
Optical SdH and other quantum oscillations in THz absorption
Abstract
Due to causality-related correspondence between static and dynamic properties of physical systems, quantum oscillation observed in a DC response must reveal their counterpart in the optical domain. In addition, the conductivity, as well as its quantum corrections, are split into real and imaginary parts in the dynamic regime. This finally leads to several novel effects in terahertz magnetooptics compared to the static results.
First, the optical analogue of the microwave-induced resistance oscillations can be seen in a transmittance signal [1]. Second, the optical counterpart of the transport Shubnikov - de Haas (SdH) oscillations can be observed. Here the dynamic nature of the optical measurements modifies the microscopic reason of the oscillations. We could demonstrate that in the case of optical SdH oscillations, a second set of magneto-oscillations appear leading to oscillation nodes and phase jumps in the observed transmission signal. And third, it is also possible to study the optical oscillations that have the same origin as transport magneto-intersubband oscillations.
These examples reveal another advantage of studying the optical response to simultaneously get the information about both, semi-classical Drude parameters and their modifications by the interaction. Considering that the optical approach does not require super-high-mobility structures or any specific fabrication processing, it can be used to study a variety of structures, including multi-valley systems and even growing family of two-dimensional crystals.
[1] M. L. Savchenko, A. Shuvaev, I. A. Dmitriev, A. A. Bykov, A. K. Bakarov, Z. D. Kvon, and A. Pimenov, Phys. Rev. Res. 3, L012013 (2021). DOI: https://doi.org/10.1103/PhysRevResearch.3.L012013