Excitonic Valley Polarization and Coherence in Few-layer MoS2

다국어 초록 (Multilingual Abstract)

We study the excitonic valley polarization and coherence in few-layer MoS2 by using circularandlinear-polarization-resolved photoluminescence. The valley polarization is largest in monolayerMoS2 and decreases with increasing number of layers or temperature. Contrary to the valleypolarization, the linear polarization is negligibly small in monolayer MoS2 and increases with increasingnumber of layers or temperature. The temperature-dependent valley depolarization canbe explained by the exciton center-of-mass momentum-dependent electron-hole exchange interaction.
The valley decoherence in few-layer MoS2 is much faster than the valley depolarization at lowtemperature and is steady against increasing temperature or photoexcitation intensity, indicatingthat the decoherence process does not involve phonon or carrier-carrier scattering. The dominantvalley decoherence has a pure dephasing origin and cannot be explained by the valley-depolarizinge-h exchange interaction.

참고문헌 (Reference)

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