# Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

@article{Braun2016UltrafastPA, title={Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3}, author={Lukas Braun and Gregor Mussler and A. Hruban and Marcin Konczykowski and Thomas Schumann and Martin Wolf and Markus M{\"u}nzenberg and Luca Perfetti and Tobias Kampfrath}, journal={Nature Communications}, year={2016}, volume={7} }

Three-dimensional topological insulators are fascinating materials with insulating bulk yet metallic surfaces that host highly mobile charge carriers with locked spin and momentum. Remarkably, surface currents with tunable direction and magnitude can be launched with tailored light beams. To better understand the underlying mechanisms, the current dynamics need to be resolved on the timescale of elementary scattering events (∼10 fs). Here, we excite and measure photocurrents in the model…

## 125 Citations

Surface State-Dominated Photoconduction and THz Generation in Topological Bi2Te2Se Nanowires

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It is demonstrated that the long surface lifetime of Bi2Te2Se nanowires allows for the access of surface states by a pulsed photoconduction scheme and that there is a prevailing bolometric response of the surface states.

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It is demonstrated that the directional photocurrent is due to the asymmetric optical transitions between topological surface states and bulk states, which is important for engineering opto-spintronic devices that rely on optical steering of spin and charge currents.

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Experimental demonstration of THz emission by the surface shift current in bulk GeSe crystals puts this 2D material forward as a candidate for next-generation shift current photovoltaics, nonlinear photonic devices, and THz sources.

Observation of spin Nernst photocurrents in topological insulators

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- 2018

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Spin Hall photoconductance in a three-dimensional topological insulator at room temperature

- PhysicsNature Communications
- 2017

Three-dimensional topological insulators are a class of Dirac materials, wherein strong spin-orbit coupling leads to two-dimensional surface states, wherein a helical, bias-dependent photoconductance at the lateral edges of topological Bi2Te2Se platelets for perpendicular incidence of light is observed.

Photocurrent measurements in topological insulator Bi 2 Se 3 nanowires

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- 2020

Circular photogalvanic currents are a promising new approach for spin-optoelectronics. To date, such currents have only been induced in topological insulator flakes or extended films. It is not clear…

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- PhysicsScientific Reports
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