Direct measurement of anharmonic decay channels of a coherent phonon
Teitelbaum, Samuel W.; Henighan, Thomas; Huang, Yijing; Liu, Hanzhe; Jiang, Mason P.; Zhu, Diling; Chollet, Matthieu; Sato, Takahiro; Murray, Éamonn D.; Fahy, Stephen B.; O'Mahony, Shane; Bailey, Trevor P.; Uher, Ctirad; Trigo, Mariano; Reis, David A.
Date:
2018-09-20
Copyright:
© 2018, American Physical Society. All rights reserved.
Citation:
Teitelbaum, S.W., Henighan, T., Huang, Y., Liu, H., Jiang, M. P., Zhu, D., Chollet, M., Sato, T., Murray, É. D., Fahy, S., O’Mahony, S., Bailey, T. P., Uher, C., Trigo, M. and Reis, D. A. (2018) 'Direct measurement of anharmonic decay channels of a coherent phonon', Physical Review Letters, 121(12), 125901 (6pp). doi:10.1103/PhysRevLett.121.125901
Abstract:
We report channel-resolved measurements of the anharmonic coupling of the coherent A1g 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 A1g frequency that are observed across the Brillouin zone by femtosecond x-ray diffuse scattering. We extract anharmonic coupling constants between the A1g and several representative decay channels that are within an order of magnitude of density functional perturbation theory calculations.
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