Population pulsation resonances of excitons in monolayer MoSe2 with sub 1 μeV linewidth

Abstract

Monolayer transition metal dichalcogenides, a new class of atomically thin semiconductors, possess optically coupled 2D valley excitons. The nature of exciton relaxation in these systems is currently poorly understood. Here, we investigate exciton relaxation in monolayer MoSe2 using polarization-resolved coherent nonlinear optical spectroscopy with high spectral resolution. We report strikingly narrow population pulsation resonances with two different characteristic linewidths of 1 μeV and <0.2 μeV at low-temperature. These linewidths are more than three orders of magnitude narrower than the photoluminescence and absorption linewidth, and indicate that a component of the exciton relaxation dynamics occurs on timescales longer than 1 ns. The ultra-narrow resonance (<0.2 μeV) emerges with increasing excitation intensity, and implies the existence of a long-lived state whose lifetime exceeds 6 ns.

(PRL, in press)

References in corpus (7)

• Valley polarization in MoS2 monolayers by optical pumping
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Making graphene visible
• Tightly bound excitons in monolayer WSe2
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Visibility of dichalcogenide nanolayers

Cited by in corpus (7)

• Exciton-exciton interaction in transition-metal dichalcogenide monolayers
• Directional Interlayer Spin-Valley Transfer in Two-Dimensional Heterostructures
• Dark excitons and the elusive valley polarization in transition metal dichalcogenides
• Observation of intervalley biexcitonic optical Stark effect in monolayer WS2
• Many-body effects in nonlinear optical responses of 2D layered semiconductors
• Sub-$\mu$eV Decoherence-Induced Population Pulsation Resonances in an InGaN system
• Steady-state nonlinear optical response of excitons in monolayer MoSe${}_2$