Phonon Dephasing Dynamics in MoS₂

Abstract

A variety of quantum degrees of freedom, e.g., spins, valleys, and localized emitters, in atomically thin van der Waals materials have been proposed for quantum information applications, and they inevitably couple to phonons. Here, we directly measure the intrinsic optical phonon decoherence in monolayer and bulk MoS 2 by observing the temporal evolution of the spectral interference of Stokes photons generated by pairs of laser pulses. We find that a prominent optical phonon mode E 2g exhibits a room-temperature dephasing time of ∼7 ps in both the monolayer and bulk. This dephasing time extends to ∼20 ps in the bulk crystal at ∼15 K, which is longer than previously thought possible. Firstprinciples calculations suggest that optical phonons decay via two types of three-phonon processes, in which a pair of acoustic phonons with opposite momentum are generated.

Enhanced double resonance Raman scattering in multilayer graphene with broadband coherent anti-Stokes Raman spectroscopy

“…Coherent phonon dephasing is an important process for understanding the light–matter interaction process and is related to quantum photonic applications. 46,47…”

“…Coherent phonon dephasing is an important process for understanding the light-matter interaction process and is related to quantum photonic applications. 46,47 For the time delay of up to 1.3 ps, the NVRB continues to have an influence on the CARS signal. After the transition from dip to peak, we model the dephasing process as a sudden stimulation in delay time T 0 and decay exponentially with a dephasing time constant…”

The mechanisms and applications of friction energy dissipation

“…Phonon describes the lattice vibration with different frequencies [43,[95][96][97][98]. Then, the phonons dissipate their energy through ultrafast processes such as electron-phonon scattering [99], phonon diphase [100], and exciton-phonon coupling [101], which determine the phonon lifetime. Ding et al [102] found that the energy accumulated in the adhesion stage and completely dissipated within 100 ps by the excitation of phonons at the Cu interface.…”

Study of Spin Localization and Charge Transport in Hydrothermally Synthesized 2H-MoS2

“…14 However, the main limitation of using these defects is the optical decoherence due to exciton−phonon coupling and spin noise. 15,16 So far, most of the basal plane defect engineering is reported either by double-step hydrothermal, annealing, and etching or by the doping method. 17−19 However, systematic evolution of defects under sulfur-deficit to sulfur-rich conditions is not well explored.…”

“…Apart from catalytic activity, the defects of MoS 2 in the 2D counterpart have also been demonstrated as the potential sources of the quantum emitter in the field of quantum information technology . However, the main limitation of using these defects is the optical decoherence due to exciton–phonon coupling and spin noise. , So far, most of the basal plane defect engineering is reported either by double-step hydrothermal, annealing, and etching or by the doping method. − However, systematic evolution of defects under sulfur-deficit to sulfur-rich conditions is not well explored.…”