Hypersonic Absorption in Quartz at Temperatures Below 30°K

Nava, R.; Azrt, R.; Ciccarello, I.; Dransfeld, Klaus

doi:10.1103/physrev.134.a581

Cited by 62 publications

(5 citation statements)

References 16 publications

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“…The three-phonon interactions can be separated into those of the type ω L + ω L → ω L and ω L + ω T → ω L , where L and T represent longitudinal and transverse polarizations, respectively. Collinear processes of the type ω L +ω L → ω L are sometimes neglected due to the dispersion of the branches, however, previous works have shown that these processes may occur as the finite lifetime of the branches compensates for the dispersion [39,40] and that they can play a large role especially at short wavevectors where the dispersion relation is quasi-linear. In fact, we find that ω L → ω L + ω L processes contribute most to the total intrinsic phonon lifetime.…”

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confidence: 99%

Lifetimes of Confined Acoustic Phonons in Ultrathin Silicon Membranes

et al. 2013

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We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultra-thin free-standing silicon membranes. Using an ultrafast pump-probe technique of asynchronous optical sampling, we observe that the decay time of the first-order dilatational mode decreases significantly from ∼ 4.7 ns to 5 ps with decreasing membrane thickness from ∼ 194 to 8 nm. The experimental results are compared with theories considering both intrinsic phonon-phonon interactions and extrinsic surface roughness scattering including a wavelength-dependent specularity. Our results provide insight to understand some of the limits of nanomechanical resonators and thermal transport in nanostructures.Mechanical and acoustic properties in the nanoscale are receiving increasing attention as they are key properties affecting the limits of ultrasensitive detectors of force [1], mass [2,3], charge [4,5] and spin [6], influencing platforms for biosensing [7] and the investigation of quantum behaviour in extended objects [8]. In particular, phonon lifetimes influence the achievable mechanical quality (Q) -factors in nanomechanical resonators, which often limit device performance [9]. Moreover, they are necessary input parameters for accurate calculations of nanoscale thermal transport, with high-impact applications such as heat management in nanoelectronics [10] and the engineering of novel thermoelectric materials [11]. Despite their importance, phonon lifetimes are perhaps the least well known of all phonon properties due to the challenges associated with their quantitative determination and theoretical modelling. Even though silicon is the most important material for nanoelectronics, MEMS and NEMS, there are few experimental reports of direct measurements of phonon lifetimes in the gigahertz to terahertz range [12] and for all materials open questions remain about the relative contributions of intrinsic and extrinsic scattering processes at high frequencies in both bulk and nanoscale structures [9,[13][14][15][16]. Recent experimental investigations of phonons in superlattice cavities with frequencies of around 1 THz have suggested that lifetimes of high-frequency phonons could be limited by an average interface roughness of just 0.06 nm [17]. On the other hand, phonon wavepackets experiments in bulk silicon with frequencies up to approximately 100 GHz were analysed with a simplified Akhiezer relaxation damping model [12,18] of intrinsic scattering, using an average lifetime of high-frequency thermal phonons of 17 ps. Other intrinsic damping models include clamping losses [19], thermoelastic dissipation [20] and three-phonon interactions [21], which predict a different behaviour depending on the frequency and temperature regimes. In this context, generation and detection of coherent acoustic phonons at high frequencies in different materials and nanostructures is an ideal method to obtain quantitative information on phonon lifetimes and compare with the main theoretical models.Here we use free-standing single-crystalline ...

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Lifetimes of Confined Acoustic Phonons in Ultrathin Silicon Membranes

et al. 2013

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“…2 'h2). (6) The simple (unweighted) average of the roomtemperature attenuation coefficients listed in Table I is a~25 dB/em. Using this value in Eq.…”

Section: Experimental Procedures and Resultsmentioning

confidence: 99%

Microwave Phonon Attenuation in Magnesium Aluminate Spinel

Lewis

Patterson

1968

Journal of Applied Physics

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Articles you may be interested inA microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces Rev. Sci. Instrum. 85, 104707 (2014); 10.1063/1.4898179 Strong asymmetrical doping properties of spinel CoAl2O4Measurements are reported of the attenuation of microwave phonons of various modes in magnesium aluminate spinel (MgAbO,). The attenuation of certain modes is lower than in any other material measured and permits the observation of 9000 MHz echo patterns at room temperature. Some possible applications of this discovery are discussed. The attenuation at room temperature is interpreted in terms of an effective viscosity damping mechanism and approximate values of the components of the viscosity matrix are given.

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“…Using estimations of the relaxation time of thermal phonons t p h , deduced from thermal conductivity data [7], we see that the condition w Zph > 1 is met. I n this case, acoustic losses are proportional t o the frequency w of the acoustic wave, t o the absolute temperature T , and t o the specific heat C,, [S] or to the number of interacting thermal phonons [9]. This would lead, at temperatures much lower than the Debye one, t o a T4 and, a t higher temperature, to a somewhat lower temperature dependence.…”

Section: Antplification and Attenuation Of Thermal Vibrationsmentioning

confidence: 99%

Current Oscillations in GaAs under Acoustic Amplification Conditions. II. Calculation of the Threshold Field

Hugon

1969

Physica Status Solidi (b)

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In the preceding paper3), experimental investigations of current oscillations in GaAs are reported. I n this paper the conditions of occurrence of a current instability is discussed in the limits of the small-signal theory. Calculated values of the threshold field and of his variations with the involved parameters are found in agreement with the experiments.Faisant suite ti 1'6tude experimentale des oscillations de courant dans GaAs rapportCe dans l'article pr6c6dent3), nous discutons ici, dans les limites de la th6orie a petits signaux. IPS conditions d'apparition d'une instabiliti! de courant. Les valeurs calculkes du champdc seuil et de sa variation avec les diff6rents paramktres sont en bon accord avec l'exp6rience.

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Hypersonic Absorption in Quartz at Temperatures Below 30°K

Cited by 62 publications

References 16 publications

Lifetimes of Confined Acoustic Phonons in Ultrathin Silicon Membranes

Lifetimes of Confined Acoustic Phonons in Ultrathin Silicon Membranes

Microwave Phonon Attenuation in Magnesium Aluminate Spinel

Current Oscillations in GaAs under Acoustic Amplification Conditions. II. Calculation of the Threshold Field

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