Photogeneration of coherent shear phonons in orientated wurtzite semiconductors by piezoelectric coupling

Wen, Yu-Chieh; Ko, Tsung-Shine; Lu, Tien−Chang; Kuo, Hao Chung; Chyi, Jen Inn; Sun, Chia‐Liang

doi:10.1103/physrevb.80.195201

Cited by 31 publications

(36 citation statements)

References 23 publications

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“…The transition from piezoelectric to deformation-potential transduction was recently demonstrated using fluence-dependent picosecond ultrasonic experiments [13][14][15] and can also be examined by our theoretical model. Here, we adopt the photoelastic model to connect our calculation with the measure of the experiments (i.e., R/R).…”

Section: Contributions Of Piezoelectricity and Deformation Potentimentioning

confidence: 62%

“…The resultant redistribution of screening carriers induces an additional electronic stress through the deformation potentials, hence giving rise to the last term in Eq. (13) and modifying the sound velocity. However, even with this nonlinear term, the modification of the sound velocity is still insignificant.…”

Section: Acoustic Waves In Doped Piezoelectric Semiconductorsmentioning

confidence: 99%

“…4,[13][14][15] To examine this effect quantitatively, we compute the amplitude and waveform of the photogenerated acoustic pulse under various pumping intensities. The inset in Fig.…”

Section: Contributions Of Piezoelectricity and Deformation Potentimentioning

confidence: 99%

“…7,8,[10][11][12][13][14][15] In this aspect, two groups 12,13 investigated the piezoelectric generation of picosecond shear waves through screening of the built-in electric fields near semiconductor surfaces with different crystal cuts. Similar photoacoustic generation was recently examined by Babilotte et al 14,15 The authors successfully explained the experimental observation on (111) GaAs surfaces by considering instantaneous screening of the surface fields.…”

Section: Introductionmentioning

confidence: 99%

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Femtosecond optical excitation of coherent acoustic phonons in a piezoelectricp-njunction

et al. 2011

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We present a theoretical model for the photogeneration of coherent acoustic phonons in a piezoelectric p-n junction. In our model, the transport of photoexcited carriers is governed by the drift-diffusion equation, whereas the dynamics of acoustic phonons obeys a loaded string equation. Among various mechanisms, the piezoelectric coupling is found to dominate the acoustic-phonon generation process. The waveform of the photogenerated acoustic pulse is strongly influenced by the various dynamics of the photoexcited carriers, especially the picosecond hole drifting. Our calculation also confirms the crucial role of the built-in electric field in the formation of coherent acoustic phonons under optical excitations.

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Section: Contributions Of Piezoelectricity and Deformation Potentimentioning

confidence: 62%

Section: Acoustic Waves In Doped Piezoelectric Semiconductorsmentioning

confidence: 99%

“…4,[13][14][15] To examine this effect quantitatively, we compute the amplitude and waveform of the photogenerated acoustic pulse under various pumping intensities. The inset in Fig.…”

Section: Contributions Of Piezoelectricity and Deformation Potentimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Femtosecond optical excitation of coherent acoustic phonons in a piezoelectricp-njunction

et al. 2011

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“…Depending on the methods of phonon generation and detection, it is possible to operate with broadband [4,5] or close to monochromatic phononic wave packets [2,6,7]. It is also possible to control phonon polarization, longitudinal or transverse, associated with compressive or shear elastic perturbations, respectively [8][9][10][11][12][13]. Information about the phonon spectrum is obtained in most of the experiments by performing a fast Fourier transform (FFT) of the optical reflectivity signal measured in the temporal domain with femtosecond resolution.…”

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confidence: 99%

Phonon Spectroscopy with Chirped Shear and Compressive Acoustic Pulses

et al. 2017

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Picosecond duration compressive and shear phonon wave packets injected into (311) GaAs slabs transform after propagation through ∼1 mm into chirped acoustic pulses with a frequency increasing in time due to phonon dispersion. By probing the temporal optical response to coherent phonons in a near surface layer of the GaAs slab, we show that phonon chirping opens a transformational route for high-sensitivity terahertz and subterahertz phonon spectroscopy. Temporal gating of the chirped phonon pulse allows the selection of a narrow band phonon spectrum with a central frequency up to 0.4 THz for longitudinal and 0.2 THz for transverse phonons. DOI: 10.1103/PhysRevLett.119.255502 Terahertz (THz) and sub-THz phonon spectroscopy has become established as a powerful tool for probing and nanoscopy of various solid objects and nanostructures. The advances achieved in this field are described in a number of reviews [1][2][3]. An important technique for THz phonon spectroscopy is based on picosecond ultrasonics developed in the 1980s by Thomsen et al. [4] and described in detail in the recent review by Matsuda et al. [5]. Depending on the methods of phonon generation and detection, it is possible to operate with broadband [4,5] or close to monochromatic phononic wave packets [2,6,7]. It is also possible to control phonon polarization, longitudinal or transverse, associated with compressive or shear elastic perturbations, respectively [8][9][10][11][12][13]. Information about the phonon spectrum is obtained in most of the experiments by performing a fast Fourier transform (FFT) of the optical reflectivity signal measured in the temporal domain with femtosecond resolution.It is a challenge to increase the sensitivity of THz phonon spectroscopy making it a more reliable instrument for studying nano-objects. This task is beyond standard technical solutions like asynchronous optical sampling (ASOPS) [14] and requires transformational physical approaches. An appealing approach, which has not yet been realized in THz phonon spectroscopy, would be to exploit chirped phonon pulses. If similar improvements could be realized as in the fields of microwaves [15] and optics [16], it would significantly improve the signal-tonoise ratio and, in the long term, open prospectives for phonon frequency, phase, and polarization control. This could be used in data processing, interference, and quantum computing, as has been proposed for chirped optical pulses [16].In the present work, we generate sub-THz and THz upchirped shear and compressive acoustic wave packets and demonstrate the potential of the technique in phonon spectroscopy by obtaining the spectrum of the photoelastic signal from probe optical pulses. The basis of the chirp effect is phonon dispersion. Because of the curving of the acoustic dispersion, 2πf ¼ cq − γq 3 (in the long-wave approximation f and q are the phonon frequency and wave vector, γ is the dispersion parameter, and c is the sound velocity) high-frequency acoustic phonons propagate slower than low-frequency ones. A...

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Equilibrium and Nonequilibrium Spectroscopy of Condensed Matter

Baldini

2018

Nonequilibrium Dynamics of Collective Excitations in Quantum Materials

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Photogeneration of coherent shear phonons in orientated wurtzite semiconductors by piezoelectric coupling

Cited by 31 publications

References 23 publications

Femtosecond optical excitation of coherent acoustic phonons in a piezoelectricp-njunction

Femtosecond optical excitation of coherent acoustic phonons in a piezoelectricp-njunction

Phonon Spectroscopy with Chirped Shear and Compressive Acoustic Pulses

Equilibrium and Nonequilibrium Spectroscopy of Condensed Matter

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