Direct Measurement of Anharmonic Decay Channels of a Coherent Phonon

We report channel-resolved measurements of the anharmonic coupling of the coherent A_{1g} phonon in photoexcited bismuth to pairs of high wave vector acoustic phonons. The decay of a coherent phonon can be understood as a parametric resonance process whereby the atomic displacement periodically modu...

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Veröffentlicht in:Physical review letters 2018-09, Vol.121 (12), p.125901-125901, Article 125901
Hauptverfasser: Teitelbaum, Samuel W, Henighan, Thomas, Huang, Yijing, Liu, Hanzhe, Jiang, Mason P, Zhu, Diling, Chollet, Matthieu, Sato, Takahiro, Murray, Éamonn D, Fahy, Stephen, O'Mahony, Shane, Bailey, Trevor P, Uher, Ctirad, Trigo, Mariano, Reis, David A
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Sprache:eng
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Zusammenfassung:We report channel-resolved measurements of the anharmonic coupling of the coherent A_{1g} phonon in photoexcited bismuth to pairs of high wave vector acoustic phonons. The decay of a coherent phonon can be understood as a parametric resonance process whereby the atomic displacement periodically modulates the frequency of a broad continuum of modes. This coupling drives temporal oscillations in the phonon mean-square displacements at the A_{1g} frequency that are observed across the Brillouin zone by femtosecond x-ray diffuse scattering. We extract anharmonic coupling constants between the A_{1g} and several representative decay channels that are within an order of magnitude of density functional perturbation theory calculations.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.121.125901