Observation of a Warped Helical Spin Texture in Bi_2Se_3 from Circular Dichroism Angle-Resolved Photoemission Spectroscopy
Abstract
A differential coupling of topological surface states to left- versus right-circularly polarized light is the basis of many optospintronics applications of topological insulators. Here we report direct evidence of circular dichroism from the surface states of Bi_2Se_3 using laser-based time-of-flight angle-resolved photoemission spectroscopy. By employing a novel sample rotational analysis, we resolve unusual modulations in the circular dichroism photoemission pattern as a function of both energy and momentum, which perfectly mimic the predicted but hitherto unobserved three-dimensional warped spin texture of the surface states. By developing a microscopic theory of photoemission from topological surface states, we show that this correlation is a natural consequence of spin-orbit coupling. These results suggest that our technique may be a powerful probe of the spin texture of spin-orbit coupled materials in general.
Additional Information
© 2011 American Physical Society Received 18 August 2011. Published 11 November 2011. This research is supported by Department of Energy Grant number DE-FG02-08ER46521, Army Research Office (ARO-DURIP) Grant number W911NF-09-1-0170 (ARTOF spectrometer) and in part by the MRSEC Program of the National Science Foundation under Grant number DMR - 0819762 (partial support for Y. H.W.).Attached Files
Published - wangEPAPS_11-06.pdf
Supplemental Material - PhysRevLett.107.207602.pdf
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Additional details
- Alternative title
- Observation of a Warped Helical Spin Texture in Bi2Se3 from Circular Dichroism Angle-Resolved Photoemission Spectroscopy
- Eprint ID
- 48511
- Resolver ID
- CaltechAUTHORS:20140813-121709306
- DE-FG02-08ER46521
- Department of Energy (DOE)
- W911NF-09-1-0170
- Army Research Office (ARO)
- DMR-0819762
- NSF
- Created
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2014-08-13Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field