Acoustic gain in piezoelectric semiconductors at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ɛ</mml:mi></mml:math>-near-zero response

Willatzen, Morten; Christensen, Johan

doi:10.1103/physrevb.89.041201

Cited by 46 publications

(28 citation statements)

References 26 publications

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“…Piezoelectric materials are usually used to convert electrical energy into mechanical energy or vice versa, and hence, have been receiving broad and sustained attention. Piezoelectric semiconductors have been used to make devices for acoustic wave amplification [21][22][23][24][25], and acoustic charge transport based on the motion of carriers under the electric field accompanying an acoustic wave.…”

Section: Introductionmentioning

confidence: 99%

Acousto-Electric Interaction in Magnetised Piezoelectric Semiconductor Quantum Plasma

Ghosh

Muley

2016

Acta Phys. Pol. A

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Amplification of an acoustic wave is considered in magnetised piezoelectric n-type semiconductor plasma under quantum hydrodynamic regime. The important ingredients of this study are the inclusion of quantum diffraction effect via the Bohm potential, statistical degeneracy pressure, and externally applied magnetostatic field in the momentum balance equation of the charged carriers. A modified dispersion relation is derived for evolution of acoustic wave by employing the linearization technique. Detailed analysis of quantum modified dispersion relation of acoustic wave is presented. For a typical parameter range, relevant to n-InSb at 77 K, it is found that the non-dimensional quantum parameter H reduces the gain while magnetic field enhances the gain of acoustic wave. The crossover from attenuation to amplification occurs at (ϑ0/ϑs) = 1 and this crossover point is found to be unaffected by quantum correction and magnetic field. It is also found that the maximum gain point shifts towards lower drift velocity regime due to the presence of magnetic field while quantum parameter H shifts this point towards higher drift velocity. Numerical results on the acoustic gain per radian and acoustic gain per unit length are also illustrated. Our results could be useful in understanding acoustic wave propagation in magnetised piezoelectric semiconductor in quantum regime.

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Section: Introductionmentioning

confidence: 99%

Acousto-Electric Interaction in Magnetised Piezoelectric Semiconductor Quantum Plasma

Ghosh

Muley

2016

Acta Phys. Pol. A

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“…[73] Importantly, the effective linear metamaterial mechanical properties around such a stable state can be significantly different for the different stable states. This behavior allows for going beyond tuning [75][76][77] in that one can rationally Prospective Article and reversibly choose a stable state. The metamaterial will then stay in that state without further external stimulus (in contrast, pure tuning requires maintaining the stimulus); see Fig.…”

Section: Anisotropic Versions Of Pentamode Metamaterialsmentioning

confidence: 99%

Vibrant times for mechanical metamaterials

Christensen¹,

et al. 2015

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Metamaterials are man-made designer matter that obtains its unusual effective properties by structure rather than chemistry. Building upon the success of electromagnetic and acoustic metamaterials, researchers working on mechanical metamaterials strive at obtaining extraordinary or extreme elasticity tensors and mass-density tensors to thereby mold static stress fields or the flow of longitudinal/transverse elastic vibrations in unprecedented ways. In this prospective paper, we focus on recent advances and remaining challenges in this emerging field. Examples are ultralight-weight, negative mass density, negative modulus, pentamode, anisotropic mass density, Origami, nonlinear, bistable, and reprogrammable mechanical metamaterials.

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“…Additionally, other emerging applications related to PT -symmetric systems [11,12], where gain and loss are combined, require the realization of materials with gain. Although gain has been introduced by means of electronic amplification in metamaterials [13] and in piezoelectric materials [14], this mechanism is difficult to implement for acoustic waves and at low frequencies, for which a more robust approach is required.…”

Section: Introductionmentioning

confidence: 99%

Loss compensation in time-dependent elastic metamaterials

2018

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Materials with properties that are modulated in time are known to display wave phenomena showing energy increasing with time, with the rate mediated by the modulation. Until now there has been no accounting for material dissipation, which clearly counteracts energy growth. This paper provides an exact expression for the amplitude of elastic or acoustic waves propagating in lossy materials with properties that are periodically modulated in time. It is found that these materials can support a special propagation regime in which waves travel at constant amplitude, with temporal modulation compensating for the normal energy dissipation. We derive a general condition under which amplification due to time-dependent properties offsets the material dissipation. This identity relates band-gap properties associated with the temporal modulation and the average of the viscosity coefficient, thereby providing a simple recipe for the design of loss-compensated mechanical metamaterials.

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Acoustic gain in piezoelectric semiconductors atɛ-near-zero response

Cited by 46 publications

References 26 publications

Acousto-Electric Interaction in Magnetised Piezoelectric Semiconductor Quantum Plasma

Acousto-Electric Interaction in Magnetised Piezoelectric Semiconductor Quantum Plasma

Vibrant times for mechanical metamaterials

Loss compensation in time-dependent elastic metamaterials

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