Nonlinear Optical Probe of Tunable Surface Electrons on a Topological Insulator
Author(s)Hsieh, David; McIver, James; Torchinsky, Darius Hosseinzadeh; Gardner, Dillon Richard; Lee, Young S.; Gedik, Nuh; ... Show more Show less
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We use ultrafast laser pulses to experimentally demonstrate that the second-order optical response of bulk single crystals of the topological insulator Bi2Se3 is sensitive to its surface electrons. By performing surface doping dependence measurements as a function of photon polarization and sample orientation we show that second harmonic generation can simultaneously probe both the surface crystalline structure and the surface charge of Bi2Se3. Furthermore, we find that second harmonic generation using circularly polarized photons reveals the time-reversal symmetry properties of the system and is surprisingly robust against surface charging, which makes it a promising tool for spectroscopic studies of topological surfaces and buried interfaces.
DepartmentMassachusetts Institute of Technology. Department of Physics
Physical Review Letters
American Physical Society
Hsieh, D. et al. "Nonlinear Optical Probe of Tunable Surface Electrons on a Topological Insulator." Phys. Rev. Lett. 106:5, 057401 (2011) © 2011 American Physical Society.
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