@article{70cd27efb3114bcf8b209a845a40a78b,
title = "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 MoS2 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 E2g 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. First-principles 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. ",
keywords = "phonon dephasing, scattering phase space, transient coherent ultrafast phonon spectroscopy, transition metal dichalcogenides",
author = "Liuyang Sun and Parveen Kumar and Zeyu Liu and Junho Choi and Bin Fang and Sebastian Roesch and Kha Tran and Joshua Casara and Eduardo Priego and Chang, {Yu Ming} and Galan Moody and Silverman, {Kevin L.} and Lorenz, {Virginia O.} and Michael Scheibner and Tengfei Luo and Xiaoqin Li",
note = "Funding Information: We acknowledge helpful discussions with Prof. R. Merlin. The spectroscopic experiments performed at UT-Austin (J.C. and X.L.) were primarily supported by the Department of Energy, Basic Energy Science program via Grant DE-SC0019398. X.L. also acknowledges partial support from NSF DMR-1808042. Partial support for L.S. and materials preparation were provided by the Welch Foundation via Grant F-1662. B.F. and K.T. are supported by the National Science Foundation through the Center for Dynamics and Control of Materials: an NSF MRSEC under Cooperative Agreement DMR-1720595. V.O.L. acknowledges support from NSF Awards 1806572 and 1521110, and M.S. acknowledges funding by the Defense Threat Reduction Agency (Award HDTRA1-15-1-0011) and the Air Force Office of Scientific Research (Award FA9550-16-1-0278). P.K. and J.C. acknowledges funding by the Merced Nanomaterials Center for Energy and Sensing. Z.L. and T.L. thank the NSF for support from the NSF 1433490 EFRI 2DARE project. The simulations are supported by the Notre Dame Center for Research Computing and by NSF through XSEDE computing resources provided by SDSC Comet and TACC Stampede under Grant TG-CTS100078. G.M. gratefully acknowledges support via the UC Santa Barbara NSF Quantum Foundry funded via the Q-AMASE-i program under award DMR-1906325. Publisher Copyright: {\textcopyright} 2021 American Chemical Society.",
year = "2021",
month = feb,
day = "10",
doi = "10.1021/acs.nanolett.0c04368",
language = "English (US)",
volume = "21",
pages = "1434--1439",
journal = "Nano Letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "3",
}