Cacho, C., Crepaldi, A., Battiato, M., Braun, J., Cilento, F., Zacchigna, M., Richter, M. C., Heckmann, O., Springate, E., Liu, Y., Dhesi, S. S., Berger, H., Bugnon, Ph., Held, K., Grioni, M., Ebert, H., Hricovini, K., Minar, J. and Parmigiani, F. (2015). Momentum-Resolved Spin Dynamics of Bulk and Surface Excited States in the Topological Insulator Bi2Se3. Phys. Rev. Lett., 114 (9). COLLEGE PK: AMER PHYSICAL SOC. ISSN 1079-7114

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Abstract

The prospect of optically inducing and controlling a spin-polarized current in spintronic devices has generated wide interest in the out-of-equilibrium electronic and spin structure of topological insulators. In this Letter we show that only measuring the spin intensity signal over several orders of magnitude by spin-, time-, and angle-resolved photoemission spectroscopy can provide a comprehensive description of the optically excited electronic states in Bi2Se3. Our experiments reveal the existence of a surface resonance state in the second bulk band gap that is benchmarked by fully relativistic ab initio spin- resolved photoemission calculations. We propose that the newly reported state plays a major role in the ultrafast dynamics of the system, acting as a bottleneck for the interaction between the topologically protected surface state and the bulk conduction band. In fact, the spin- polarization dynamics in momentum space show that these states display macroscopically different temperatures and, more importantly, different cooling rates over several picoseconds.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Cacho, C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Crepaldi, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Battiato, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Braun, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Cilento, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Zacchigna, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Richter, M. C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Heckmann, O.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Springate, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Liu, Y.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Dhesi, S. S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Berger, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bugnon, Ph.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Held, K.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Grioni, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Ebert, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Hricovini, K.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Minar, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Parmigiani, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-410045
DOI: 10.1103/PhysRevLett.114.097401
Journal or Publication Title: Phys. Rev. Lett.
Volume: 114
Number: 9
Date: 2015
Publisher: AMER PHYSICAL SOC
Place of Publication: COLLEGE PK
ISSN: 1079-7114
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
PHOTOEMISSION; MANIPULATION; TEXTURE; BI2TE3Multiple languages
Physics, MultidisciplinaryMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/41004

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