Bulletin of the American Physical Society
APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014; Denver, Colorado
Session B51: Focus Session: Beyond Graphene: Synthesis, Defects, Structure, and Properties II
11:15 AM–2:15 PM,
Monday, March 3, 2014
Room: Mile High Ballroom 1E
Sponsoring Unit: DMP
Chair: Xiaodong Xu, University of Washington
Abstract ID: BAPS.2014.MAR.B51.4
Abstract: B51.00004 : Optoelectronic Control of Spin and Pseudospin in Layered WSe$_2$*
11:51 AM–12:27 PM
Preview Abstract Abstract
(University of Washington)
Coherent manipulation of spin-like quantum numbers facilitates the development of new quantum technologies. Layered transition metal dichalcogenides provide an ideal laboratory to exploit such dynamic control of spin, pseudospin, and their interplay. Here, we discuss two examples based on monolayer and bilayer WSe$_2$. Due to the inversion asymmetry in monolayer WSe$_2$, valley pseudospins, which index the degenerate extrema of the energy-momentum bands, possess circularly polarized optical selection rules. In addition to the generation of valley polarization through optical pumping of valley excitons, we demonstrate the creation of a coherent superposition between valley states in monolayer WSe$_2$ by linearly polarized excitation. On the other hand, bilayer WSe$_2$ provides an additional quantum degree of freedom, the layer pseudospin, which corresponds to layer polarization. In AB stacked bilayers, we find the real spin is locked to layer pseudospin for a given valley, which results in the suppression of spin relaxation and electrical control of spin Zeeman splitting without an applied magnetic field. Additionally, we obtain spectroscopic evidence of interlayer and intralayer trion species, an important step toward coherent optical control in van der Waals 2D heterostructures.
*Aaron Jones partially supported by NSF Grant No. DGE-0718124.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.B51.4
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