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arXiv · 2305.04362

Strongly coupled interface electronic states and interface phonon mode at GaP/Si(001)

Gerson Mette·Kunie Ishioka·Steven Youngkin·Wolfgang Stolz·Kerstin Volz·Ulrich Höfer
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Abstract

Ultrafast carrier and phonon dynamics at the buried heterointerface of GaP/Si(001) are investigated by means of two-color pump-probe reflectivity measurements. The carrier-induced reflectivity signal exhibits a resonant enhancement at pump-photon energies of 1.4 eV, which can be assigned to an optical transition between electronic interface states. The transient reflectivity is modulated by a coherent oscillation at 2 THz, whose amplitude also becomes maximum at 1.4 eV. The observed resonant behavior of the phonon mode in combination with a characteristic wavelength-dependence of, both, its frequency and initial phase, strongly indicate that the 2-THz mode is a difference-combination mode of a GaP-like and a Si-like phonon at the heterointerface and that this second-order scattering process can be enhanced by a double resonance involving the interfacial electronic states.

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Gerson Mette, Kunie Ishioka, Steven Youngkin, Wolfgang Stolz, Kerstin Volz, Ulrich Höfer. 2023-05-07. Strongly coupled interface electronic states and interface phonon mode at GaP/Si(001). https://doi.org/10.1002/admi.202400573

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