Seminars Archive

Fri 21 Jun, at 11:30 - Seminar Room T1

Observation of Valley-Selective Linear Dichroism in Bilayer MoS2

Charlotte Sanders
Central Laser Facility, UK

It is by now well understood that circular dichroism arises in single-layer trigonal prismatic MoS2 due to the lack of inversion symmetry in the single layer and to the resultant spin polarization of the valence band at the K and K’ points of the Brillouin zone. In the simplest picture, then, one might expect to see no dichroism at all in bilayer MoS2, where inversion symmetry is restored. Nevertheless, our recent results obtained by pump-probe angle-resolved photoemission spectroscopy at the U.K. Artemis material science beamline reveal a strong and previously unpredicted linear dichroism at K and K’. In this talk, I will discuss these results and explain how they arise intrinsically, in connection with the trigonal warping of the valence band in the K and K’ valleys. I will also present a brief update on the status of the Artemis user facility’s upgrades to a new 100-kHz laser source.

(Referer: F. Cilento)
Last Updated on Tuesday, 24 April 2012 15:21