A cascading nonlinear magneto-optical effect in topological insulators
Abstract
Topological insulators (TIs) are characterized by possessing metallic (gapless) surface states and a finite band-gap state in the bulk. As the thickness of a TI layer decreases down to a few nanometer, hybridization between the top and bottom surfaces takes place due to quantum tunneling, consequently at a critical thickness a crossover from a 3D-TI to a 2D insulator occurs. Although such a crossover is generally accessible by scanning tunneling microscopy, or by angle-resolved photoemission spectroscopy, such measurements require clean surfaces. Here, we demonstrate that a cascading nonlinear magneto-optical effect induced via strong spin-orbit coupling can examine such crossovers. The helicity dependence of the time-resolved Kerr rotation exhibits a robust change in periodicity at a critical thickness, from which it is possible to predict the formation of a Dirac cone in a film several quintuple layers thick. This method enables prediction of a Dirac cone using a fundamental nonlinear optical effect that can be applied to a wide range of TIs and related 2D materials.
Cite
@article{arxiv.1803.01490,
title = {A cascading nonlinear magneto-optical effect in topological insulators},
author = {Richarj Mondal and Yuta Saito and Yuki Aihara and Paul Fons and Alexander V. Kolobov and Junji Tominaga and Shuichi Murakami and Muneaki Hase},
journal= {arXiv preprint arXiv:1803.01490},
year = {2018}
}
Comments
7 pages, 6 figures