laboratoire pierre aigrain
électronique et photonique quantiques
laboratoire pierre aigrain

Seminar, 10th October 2016 (15h salle L363/L365)

Ning Wang (Hong Kong University of Science and Technology, China)
Even-Odd Layer-Dependent Magnetotransport of High Mobility Q-Valley Electrons in Few-Layer Transition Metal Disulfides

In few-layer transition metal dichalcogenides (TMDCs), the conduction
bands along the ΓK directions shift downward energetically in the
presence of interlayer interactions, forming six Q valleys related by
three-fold rotational symmetry and time reversal symmetry. In
even-layers the extra inversion symmetry requires all states to be
Kramers degenerate, whereas in odd-layers the intrinsic inversion
asymmetry dictates the Q valleys to be spin-valley coupled. Here we
report the transport characterization of prominent Shubnikov-de Hass
(SdH) oscillations and the observation of the onset of quantum Hall
plateaus for the Q valley electrons in few-layer TMDCs. Universally in
the SdH oscillations, we observe a valley Zeeman effect in all odd-layer
TMDC devices and a spin Zeeman effect in all even-layer TMDC devices.