TY - JOUR
T1 - Comparison of coherent phonon generation by electronic and ionic Raman scattering in LaAlO3
AU - Neugebauer, Martin J.
AU - Juraschek, Dominik M.
AU - Savoini, Matteo
AU - Engeler, Pascal
AU - Boie, Larissa
AU - Abreu, Elsa
AU - Spaldin, Nicola A.
AU - Johnson, Steven L.
N1 - Publisher Copyright:
© 2021 authors.
PY - 2021/2/10
Y1 - 2021/2/10
N2 - In ionic Raman scattering, infrared-active phonons mediate a scattering process that results in the creation or destruction of a Raman-active phonon. This mechanism relies on nonlinear interactions between phonons and has in recent years been associated with a variety of emergent lattice-driven phenomena in complex transition-metal oxides, but the underlying mechanism is often obscured by the presence of multiple coupled order parameters in play. Here, we use time-resolved spectroscopy to compare coherent phonons generated by ionic Raman scattering with those created by more conventional electronic Raman scattering on the nonmagnetic and non-strongly-correlated wide-band-gap insulator LaAlO3. We find that the oscillatory amplitude of the low-frequency Raman-active Eg mode exhibits a sharp peak when we tune our pump frequency into resonance with the high-frequency infrared-active Eu mode, consistent with first-principles calculations. Our results suggest that ionic Raman scattering can strongly dominate electronic Raman scattering in wide-band-gap insulating materials. We also see evidence of competing scattering channels at fluences above 28mJ/cm2 that alter the measured amplitude of the coherent phonon response.
AB - In ionic Raman scattering, infrared-active phonons mediate a scattering process that results in the creation or destruction of a Raman-active phonon. This mechanism relies on nonlinear interactions between phonons and has in recent years been associated with a variety of emergent lattice-driven phenomena in complex transition-metal oxides, but the underlying mechanism is often obscured by the presence of multiple coupled order parameters in play. Here, we use time-resolved spectroscopy to compare coherent phonons generated by ionic Raman scattering with those created by more conventional electronic Raman scattering on the nonmagnetic and non-strongly-correlated wide-band-gap insulator LaAlO3. We find that the oscillatory amplitude of the low-frequency Raman-active Eg mode exhibits a sharp peak when we tune our pump frequency into resonance with the high-frequency infrared-active Eu mode, consistent with first-principles calculations. Our results suggest that ionic Raman scattering can strongly dominate electronic Raman scattering in wide-band-gap insulating materials. We also see evidence of competing scattering channels at fluences above 28mJ/cm2 that alter the measured amplitude of the coherent phonon response.
UR - http://www.scopus.com/inward/record.url?scp=85115894431&partnerID=8YFLogxK
U2 - 10.1103/PhysRevResearch.3.013126
DO - 10.1103/PhysRevResearch.3.013126
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AN - SCOPUS:85115894431
SN - 2643-1564
VL - 3
JO - Physical Review Research
JF - Physical Review Research
IS - 1
M1 - 013126
ER -