Details

Autor(en) / Beteiligte

• Langer, F
• Schmid, C P
• Schlauderer, S
• Gmitra, M
• Fabian, J
• Nagler, P
• Schüller, C
• Korn, T
• Hawkins, P G
• Steiner, J T
• Huttner, U
• Koch, S W
• Kira, M
• Huber, R

Titel

Lightwave valleytronics in a monolayer of tungsten diselenide

Ist Teil von

• Nature (London), 2018-05, Vol.557 (7703), p.76-80

Ort / Verlag

England: Nature Publishing Group

Erscheinungsjahr

2018

Link zum Volltext

Beschreibungen/Notizen

• As conventional electronics approaches its limits , nanoscience has urgently sought methods of fast control of electrons at the fundamental quantum level . Lightwave electronics -the foundation of attosecond science -uses the oscillating carrier wave of intense light pulses to control the translational motion of the electron's charge faster than a single cycle of light . Despite being particularly promising information carriers, the internal quantum attributes of spin and valley pseudospin have not been switchable on the subcycle scale. Here we demonstrate lightwave-driven changes of the valley pseudospin and introduce distinct signatures in the optical readout. Photogenerated electron-hole pairs in a monolayer of tungsten diselenide are accelerated and collided by a strong lightwave. The emergence of high-odd-order sidebands and anomalous changes in their polarization direction directly attest to the ultrafast pseudospin dynamics. Quantitative computations combining density functional theory with a non-perturbative quantum many-body approach assign the polarization of the sidebands to a lightwave-induced change of the valley pseudospin and confirm that the process is coherent and adiabatic. Our work opens the door to systematic valleytronic logic at optical clock rates.