Picosecond expansion in LaAlO3 resonantly driven by infrared-active phonons
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866912166403112960 |
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| author | Gollwitzer, Jakob Kaaret, Jeffrey Z. Suyolcu, Y. Eren Khalsa, Guru Fernandes, Rylan C. Gorobtsov, Oleg Buchenau, Sören You, ChanJu Higgins, Jayanti Russell, Ryan S. Shao, Ziming Birkhölzer, Yorick A. Sato, Takahiro Chollet, Matthieu Coslovich, Giacomo Brützam, Mario Guguschev, Christo Harter, John W. Disa, Ankit S. Schlom, Darrell G. Benedek, Nicole A. Singer, Andrej |
| author_facet | Gollwitzer, Jakob Kaaret, Jeffrey Z. Suyolcu, Y. Eren Khalsa, Guru Fernandes, Rylan C. Gorobtsov, Oleg Buchenau, Sören You, ChanJu Higgins, Jayanti Russell, Ryan S. Shao, Ziming Birkhölzer, Yorick A. Sato, Takahiro Chollet, Matthieu Coslovich, Giacomo Brützam, Mario Guguschev, Christo Harter, John W. Disa, Ankit S. Schlom, Darrell G. Benedek, Nicole A. Singer, Andrej |
| contents | We investigate the ultrafast structural dynamics of LaAlO3 thin films driven by short mid-infrared laser pulses at 20 THz. Time-resolved X-ray diffraction reveals an immediate lattice expansion and an acoustic breathing mode of the film. First-principles theory and a spring-mass model identify the direct coupling between coherently driven infrared-active phonons and strain as the underlying mechanism. Time-resolved optical birefringence measurements confirm that the amplitude of this acoustic mode scales linearly with the pump fluence, which agrees with the theory. Furthermore, time-resolved X-ray diffuse scattering indicates that THz excitation enhances crystallinity by inducing a non-thermal increase in structural symmetry originating from preexisting defects. These findings highlight the potential of a multimodal approach-combining time-resolved X-ray and optical measurements and first-principles theory-to elucidate and control structural dynamics in nanoscale materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_17192 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Picosecond expansion in LaAlO3 resonantly driven by infrared-active phonons Gollwitzer, Jakob Kaaret, Jeffrey Z. Suyolcu, Y. Eren Khalsa, Guru Fernandes, Rylan C. Gorobtsov, Oleg Buchenau, Sören You, ChanJu Higgins, Jayanti Russell, Ryan S. Shao, Ziming Birkhölzer, Yorick A. Sato, Takahiro Chollet, Matthieu Coslovich, Giacomo Brützam, Mario Guguschev, Christo Harter, John W. Disa, Ankit S. Schlom, Darrell G. Benedek, Nicole A. Singer, Andrej Materials Science We investigate the ultrafast structural dynamics of LaAlO3 thin films driven by short mid-infrared laser pulses at 20 THz. Time-resolved X-ray diffraction reveals an immediate lattice expansion and an acoustic breathing mode of the film. First-principles theory and a spring-mass model identify the direct coupling between coherently driven infrared-active phonons and strain as the underlying mechanism. Time-resolved optical birefringence measurements confirm that the amplitude of this acoustic mode scales linearly with the pump fluence, which agrees with the theory. Furthermore, time-resolved X-ray diffuse scattering indicates that THz excitation enhances crystallinity by inducing a non-thermal increase in structural symmetry originating from preexisting defects. These findings highlight the potential of a multimodal approach-combining time-resolved X-ray and optical measurements and first-principles theory-to elucidate and control structural dynamics in nanoscale materials. |
| title | Picosecond expansion in LaAlO3 resonantly driven by infrared-active phonons |
| topic | Materials Science |
| url | https://arxiv.org/abs/2412.17192 |