Open AccessTheoretical and experimental study of second harmonic generation from the surface of the topological insulator Bi2 3
Author(s) -
James McIver,
David Hsieh,
Steven Drapcho,
Darius Torchinsky,
Dillon Gardner,
Y. S. Lee,
Nuh Gedik
Publication year - 2012
Publication title -
physical review. b, condensed matter and materials physics
Language(s) - English
Resource type - Journals
eISSN - 1538-4489
pISSN - 1098-0121
DOI - 10.1103/physrevb.86.035327
Subject(s) - topological insulator , second harmonic generation , polarization (electrochemistry) , physics , high harmonic generation , tensor (intrinsic definition) , topology (electrical circuits) , laser , nonlinear optics , optics , nonlinear system , condensed matter physics , quantum mechanics , geometry , chemistry , mathematics , combinatorics
We develop a theoretical model that describes the second harmonic generation of light from the surface of the topological insulator Bi[subscript 2]Se[subscript 3] and experimentally demonstrate that the technique is sensitive to the surface electrons. By performing a crystal symmetry analysis of Bi[subscript 2]Se[subscript 3](111) we determine the nonlinear electric susceptibility tensor elements that give rise to second harmonic generation. Using these results, we present a phenomenological model that shows that the relative magnitudes of these tensor elements can be determined by measuring the polarization and intensity of the radiated second harmonic light as a function of the in-plane crystal orientation and incident laser polarization. We describe optical techniques capable of isolating second harmonic light and, using these techniques, we measure the first-order linear optical and second-order nonlinear optical responses as a function of crystal orientation and laser polarization on bulk single crystals of Bi[subscript 2]Se[subscript 3](111). The experimental results are consistent with our theoretical description. By comparing the data to our theoretical model we determine that a portion of the measured second harmonic light originates from the accumulation region of Bi[subscript 2]Se[subscript 3](111), which we confirm by performing surface doping-dependent studies. Our results show that second harmonic generation is a promising tool for spectroscopic studies of topological surfaces and buried interfaces.United States. Dept. of Energy (DE-FG02- 08ER46521