<div class="csl-bib-body">
<div class="csl-entry">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., Minár, J., & Parmigiani, F. (2015). Momentum-Resolved Spin Dynamics of Bulk and Surface Excited States in the Topological Insulator Bi₂Se₃. <i>Physical Review Letters</i>, <i>114</i>(097401). https://doi.org/10.1103/physrevlett.114.097401</div>
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dc.identifier.issn
0031-9007
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/151480
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dc.description.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.
en
dc.language.iso
en
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dc.publisher
AMER PHYSICAL SOC
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dc.relation.ispartof
Physical Review Letters
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dc.subject
General Physics and Astronomy
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dc.title
Momentum-Resolved Spin Dynamics of Bulk and Surface Excited States in the Topological Insulator Bi₂Se₃