Electronic valleys refer to energy extrema in momentum space. In the same way as spin is utilized for spintronics, valleys can be considered as pseudo-spins for valley based electronics and optoelectronics. Although the concept of valleytronics has been proposed for many years, progress has been hampered by a lack of ideal physical systems, in particular for optically driven valleytronics. Here, we show that monolayer group VI transition metal dichalcogenides is a promising system to meet this challenge. In particular, there are circularly polarized optical selection rules associated with valley index, which allows addressing the individual valleys by optical means. We further demonstrate optical generation of valley polarization using monolayer MoS₂ as a model system. Our results open the door for optical investigation of valley physics in monolayer semiconductors.

Date Published: 29 March 2013
PDF: 6 pages
Proc. SPIE 8635, Advances in Photonics of Quantum Computing, Memory, and Communication VI, 86350A (29 March 2013); doi: 10.1117/12.2003425

Published in SPIE Proceedings Vol. 8635:
Advances in Photonics of Quantum Computing, Memory, and Communication VI
Zameer U. Hasan; Philip R. Hemmer; Hwang Lee; Charles M. Santori, Editor(s)