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arXiv · 1908.07161

Measurements of Nonequilibrium Interatomic Forces in Photoexcited Bismuth

Samuel W. Teitelbaum·Thomas C. Henighan·Hanzhe Liu·Mason P. Jiang·Diling Zhu·Matthieu Chollet·Takahiro Sato·Éamonn D. Murray·Stephen Fahy·Shane O'Mahony·Trevor P. Bailey·Ctirad Uher·Mariano Trigo·David A. Reis
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Abstract

We determine experimentally the excited-state interatomic forces in photoexcited bismuth. The forces are obtained by a constrained least-squares fit of the excited-state dispersion obtained by femtosecond time-resolved x-ray diffuse scattering to a fifteen-nearest neighbor Born-von Karman model. We find that the observed softening of the zone-center $A_{1g}$ optical mode and transverse acoustic modes with photoexcitation are primarily due to a weakening of three nearest neighbor forces along the bonding direction. This provides a more complete picture of what drives the partial reversal of the Peierls distortion previously observed in photoexcited bismuth.

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Samuel W. Teitelbaum, Thomas C. Henighan, Hanzhe Liu, Mason P. Jiang, Diling Zhu, Matthieu Chollet, Takahiro Sato, Éamonn D. Murray, Stephen Fahy, Shane O'Mahony, Trevor P. Bailey, Ctirad Uher, Mariano Trigo, David A. Reis. 2019-08-20. Measurements of Nonequilibrium Interatomic Forces in Photoexcited Bismuth. https://doi.org/10.1103/physrevb.103.l180101

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