Pub Date : 2020-08-11DOI: 10.1103/PHYSREVAPPLIED.15.014046
H. Li, A. Thayil, C. Lew, M. Filoche, B. C. Johnson, J. McCallum, S. Arscott, A. Rowe
The steady-state, space-charge-limited piezoresistance (PZR) of defect-engineered, silicon-on-insulator device layers containing silicon divacancy defects changes sign as a function of applied bias. Above a punch-through voltage ($V_t$) corresponding to the onset of a space-charge-limited hole current, the longitudinal $langle 110 rangle$ PZR $pi$-coefficient is $pi approx 65 times 10^{-11}$~Pa$^{-1}$, similar to the value obtained in charge-neutral, p-type silicon. Below $V_t$, the mechanical stress dependence of the Shockley-Read-Hall (SRH) recombination parameters, specifically the divacancy trap energy $E_T$ which is estimated to vary by $approx 30$~$mu$V/MPa, yields $pi approx -25 times 10^{-11}$~Pa$^{-1}$. The combination of space-charge-limited transport and defect engineering which significantly reduces SRH recombination lifetimes makes this work directly relevant to discussions of giant or anomalous PZR at small strains in nano-silicon whose characteristic dimension is larger than a few nanometers. In this limit the reduced electrostatic dimensionality lowers $V_t$ and amplifies space-charge-limited currents and efficient SRH recombination occurs via surface defects. The results reinforce the growing evidence that in steady state, electro-mechanically active defects can result in anomalous, but not giant, PZR.
含有硅间隙缺陷的绝缘体上硅器件层的稳态、空间电荷限制压阻(PZR)随施加偏置的函数而变化。在对应于空间电荷限制空穴电流起始的穿孔电压($V_t$)以上，纵向$langle 110 rangle$ PZR $pi$ -系数为$pi approx 65 times 10^{-11}$ Pa $^{-1}$，类似于在电荷中性的p型硅中获得的值。在$V_t$下面，Shockley-Read-Hall (SRH)复合参数的机械应力依赖关系，特别是距离陷阱能量$E_T$，估计变化为$approx 30$$mu$ V/MPa，得到$pi approx -25 times 10^{-11}$ Pa $^{-1}$。空间电荷限制输运和缺陷工程的结合显著降低了SRH重组寿命，这使得这项工作与纳米硅中特征尺寸大于几纳米的小应变下的巨大或异常PZR的讨论直接相关。在这个极限下，降低的静电维数降低$V_t$并放大空间电荷限制电流，通过表面缺陷发生有效的SRH重组。结果强化了越来越多的证据，即在稳态下，机电活性缺陷可以导致异常的PZR，但不会导致巨大的PZR。
{"title":"Piezoresistance in Defect-Engineered Silicon","authors":"H. Li, A. Thayil, C. Lew, M. Filoche, B. C. Johnson, J. McCallum, S. Arscott, A. Rowe","doi":"10.1103/PHYSREVAPPLIED.15.014046","DOIUrl":"https://doi.org/10.1103/PHYSREVAPPLIED.15.014046","url":null,"abstract":"The steady-state, space-charge-limited piezoresistance (PZR) of defect-engineered, silicon-on-insulator device layers containing silicon divacancy defects changes sign as a function of applied bias. Above a punch-through voltage ($V_t$) corresponding to the onset of a space-charge-limited hole current, the longitudinal $langle 110 rangle$ PZR $pi$-coefficient is $pi approx 65 times 10^{-11}$~Pa$^{-1}$, similar to the value obtained in charge-neutral, p-type silicon. Below $V_t$, the mechanical stress dependence of the Shockley-Read-Hall (SRH) recombination parameters, specifically the divacancy trap energy $E_T$ which is estimated to vary by $approx 30$~$mu$V/MPa, yields $pi approx -25 times 10^{-11}$~Pa$^{-1}$. The combination of space-charge-limited transport and defect engineering which significantly reduces SRH recombination lifetimes makes this work directly relevant to discussions of giant or anomalous PZR at small strains in nano-silicon whose characteristic dimension is larger than a few nanometers. In this limit the reduced electrostatic dimensionality lowers $V_t$ and amplifies space-charge-limited currents and efficient SRH recombination occurs via surface defects. The results reinforce the growing evidence that in steady state, electro-mechanically active defects can result in anomalous, but not giant, PZR.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77872378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-10DOI: 10.1103/physrevb.102.195129
D. Dobrykh, D. Shakirova, S. Krasikov, A. Mikhailovskaya, I. Yusupov, A. Slobozhanyuk, K. Ladutenko, D. Filonov, A. Bogdanov, P. Ginzburg
An efficient modulation of backscattered energy is one of the key requirements for enabling efficient wireless communication channels. Typical architectures, being based on either electronically or mechanically modulated reflectors, cannot be downscaled to subwavelengths dimensions by design. Here we show that integrating high-index dielectric materials with tunable subwavelength resonators allows achieving an efficient backscattering modulation, keeping a footprint of an entire structure small. An interference between high-order Mie resonances leads to either enhancement or suppression of the backscattering, depending on a control parameter. In particular, a ceramic core-shell, driven by an electronically tunable split ring resonator was shown to provide a backscattering modulation depth as high as tens of the geometrical cross-section of the structure. The design was optimized towards maximizing reading range of radio frequency identification (RFID) tags and shown to outperform existing commercial solutions by orders of magnitude in terms of the modulation efficiency. The proposed concept of multipole engineering allows one to design a new generation of miniature beacons and modulators for wireless communication needs and other relevant applications.
{"title":"Multipole engineering for enhanced backscattering modulation","authors":"D. Dobrykh, D. Shakirova, S. Krasikov, A. Mikhailovskaya, I. Yusupov, A. Slobozhanyuk, K. Ladutenko, D. Filonov, A. Bogdanov, P. Ginzburg","doi":"10.1103/physrevb.102.195129","DOIUrl":"https://doi.org/10.1103/physrevb.102.195129","url":null,"abstract":"An efficient modulation of backscattered energy is one of the key requirements for enabling efficient wireless communication channels. Typical architectures, being based on either electronically or mechanically modulated reflectors, cannot be downscaled to subwavelengths dimensions by design. Here we show that integrating high-index dielectric materials with tunable subwavelength resonators allows achieving an efficient backscattering modulation, keeping a footprint of an entire structure small. An interference between high-order Mie resonances leads to either enhancement or suppression of the backscattering, depending on a control parameter. In particular, a ceramic core-shell, driven by an electronically tunable split ring resonator was shown to provide a backscattering modulation depth as high as tens of the geometrical cross-section of the structure. The design was optimized towards maximizing reading range of radio frequency identification (RFID) tags and shown to outperform existing commercial solutions by orders of magnitude in terms of the modulation efficiency. The proposed concept of multipole engineering allows one to design a new generation of miniature beacons and modulators for wireless communication needs and other relevant applications.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81853634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-10DOI: 10.1103/PhysRevApplied.14.024022
F. De Nicola, S. Sarti, Bing Lu, L. Qu, Zhipan Zhang, A. Marcelli, S. Lupi
Sound is usually generated in a medium by an electromechanical vibrating structure. The geometrical size and inertia of the structure set the frequency cutoff in the sound-transduction mechanism and, often, different vibrating structures are necessary to cover the whole range from infrasound to ultrasound. An alternative mechanism without any physical movement of the emitter is the thermoacoustic effect, where sound is produced by Joule heating in a conductive material. Here we show that a single thermoacoustic transducer based on a graphene aerogel can emit ultrabroadband sound from infrasound (1 Hz) to ultrasound (20 MHz), with no harmonic distortion. Since conventional acoustic transducers are frequency band limited due to their transduction mechanism, ultrabroadband graphene aerogels may offer a valid alternative to conventional hi-fi loudspeakers, and infrasound and ultrasound transducers.
{"title":"Graphene Aerogels for Ultrabroadband Thermoacoustics","authors":"F. De Nicola, S. Sarti, Bing Lu, L. Qu, Zhipan Zhang, A. Marcelli, S. Lupi","doi":"10.1103/PhysRevApplied.14.024022","DOIUrl":"https://doi.org/10.1103/PhysRevApplied.14.024022","url":null,"abstract":"Sound is usually generated in a medium by an electromechanical vibrating structure. The geometrical size and inertia of the structure set the frequency cutoff in the sound-transduction mechanism and, often, different vibrating structures are necessary to cover the whole range from infrasound to ultrasound. An alternative mechanism without any physical movement of the emitter is the thermoacoustic effect, where sound is produced by Joule heating in a conductive material. Here we show that a single thermoacoustic transducer based on a graphene aerogel can emit ultrabroadband sound from infrasound (1 Hz) to ultrasound (20 MHz), with no harmonic distortion. Since conventional acoustic transducers are frequency band limited due to their transduction mechanism, ultrabroadband graphene aerogels may offer a valid alternative to conventional hi-fi loudspeakers, and infrasound and ultrasound transducers.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82533308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-10DOI: 10.1103/physrevapplied.14.064003
Juan Zhao, Yibin Hu, Yiqun Xie, Lei Zhang, Yin Wang
Photogalvanic effect (PGE) occurring in noncentrosymmetric materials enables the generation of the open-circuit voltage that is much larger than the bandgap, making it rather attractive in solar cells. However, the magnitude of the PGE photocurrent is usually small, which severely hampers its practical application. Here we propose a mechanism to largely enhance the PGE photocurrent by mechanical strain based on the quantum transport simulations for the two-dimensional nickel-phosphorene-nickel photodetector. Broadband PGE photocurrent governed by the Cs noncentrosymmetry is generated at zero bias under the illumination of linearly polarized light. The photocurrent depends linearly on the device asymmetry, while nonlinearly on the optical absorption. By applying the appropriate mechanical tension stress on the phosphorene, the photocurrent can be substantially enhanced by up to 3 orders of magnitude, which is primarily ascribed to the largely increased device asymmetry. The change in the optical absorption in some cases can also play a critical role in tuning the photocurrent due to the nonlinear dependence. Moreover, the photocurrent can even be further enhanced by the mechanical bending, mainly owing to the considerably enhanced device asymmetry. Our results reveal the dependence of the PGE photocurrent on the device asymmetry and absorption in transport process through a device, and also explore the potentials of the PGE in the self-powered low-dimensional flexible optoelectronics.
{"title":"Largely Enhanced Photogalvanic Effects in a Phosphorene Photodetector by Strain-Increased Device Asymmetry","authors":"Juan Zhao, Yibin Hu, Yiqun Xie, Lei Zhang, Yin Wang","doi":"10.1103/physrevapplied.14.064003","DOIUrl":"https://doi.org/10.1103/physrevapplied.14.064003","url":null,"abstract":"Photogalvanic effect (PGE) occurring in noncentrosymmetric materials enables the generation of the open-circuit voltage that is much larger than the bandgap, making it rather attractive in solar cells. However, the magnitude of the PGE photocurrent is usually small, which severely hampers its practical application. Here we propose a mechanism to largely enhance the PGE photocurrent by mechanical strain based on the quantum transport simulations for the two-dimensional nickel-phosphorene-nickel photodetector. Broadband PGE photocurrent governed by the Cs noncentrosymmetry is generated at zero bias under the illumination of linearly polarized light. The photocurrent depends linearly on the device asymmetry, while nonlinearly on the optical absorption. By applying the appropriate mechanical tension stress on the phosphorene, the photocurrent can be substantially enhanced by up to 3 orders of magnitude, which is primarily ascribed to the largely increased device asymmetry. The change in the optical absorption in some cases can also play a critical role in tuning the photocurrent due to the nonlinear dependence. Moreover, the photocurrent can even be further enhanced by the mechanical bending, mainly owing to the considerably enhanced device asymmetry. Our results reveal the dependence of the PGE photocurrent on the device asymmetry and absorption in transport process through a device, and also explore the potentials of the PGE in the self-powered low-dimensional flexible optoelectronics.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72980521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-08-01DOI: 10.1103/PHYSREVAPPLIED.15.014018
N. K. Paul, J. S. Gómez-Díaz
We propose the optical trapping of Rayleigh particles using tailored anisotropic and hyperbolic metasurfaces illuminated with a linearly polarized Gaussian beam. This platform permits to engineer optical traps at the beam axis with a response governed by nonconservative and giant recoil forces coming from the directional excitation of ultra-confined surface plasmons during the light scattering process. Compared to optical traps set over bulk metals, the proposed traps are broadband in the sense that can be set with beams oscillating at any frequency within the wide range in which the metasurface supports surface plasmons. Over that range, the metasurface evolves from an anisotropic elliptic to a hyperbolic regime through a topological transition and enables optical traps with distinctive spatially asymmetric potential distribution, local potential barriers arising from the momentum imbalance of the excited plasmons, and an enhanced potential depth that permits the stable trapping of nanoparticles using low-intensity laser beams. To investigate the performance of this platform, we develop a rigorous formalism based on the Lorentz force within the Rayleigh approximation combined with anisotropic Green's functions and calculate the trapping potential of nonconservative forces using the Helmholtz-Hodge decomposition method. Tailored anisotropic and hyperbolic metasurfaces, commonly implemented by nanostructuring thin metallic layers, enables using low-intensity laser sources operating in the visible or the IR to trap and manipulate particles at the nanoscale, and may enable a wide range of applications in bioengineering, physics, and chemistry.
{"title":"Low-power Optical Traps Using Anisotropic Metasurfaces: Asymmetric Potential Barriers and Broadband Response","authors":"N. K. Paul, J. S. Gómez-Díaz","doi":"10.1103/PHYSREVAPPLIED.15.014018","DOIUrl":"https://doi.org/10.1103/PHYSREVAPPLIED.15.014018","url":null,"abstract":"We propose the optical trapping of Rayleigh particles using tailored anisotropic and hyperbolic metasurfaces illuminated with a linearly polarized Gaussian beam. This platform permits to engineer optical traps at the beam axis with a response governed by nonconservative and giant recoil forces coming from the directional excitation of ultra-confined surface plasmons during the light scattering process. Compared to optical traps set over bulk metals, the proposed traps are broadband in the sense that can be set with beams oscillating at any frequency within the wide range in which the metasurface supports surface plasmons. Over that range, the metasurface evolves from an anisotropic elliptic to a hyperbolic regime through a topological transition and enables optical traps with distinctive spatially asymmetric potential distribution, local potential barriers arising from the momentum imbalance of the excited plasmons, and an enhanced potential depth that permits the stable trapping of nanoparticles using low-intensity laser beams. To investigate the performance of this platform, we develop a rigorous formalism based on the Lorentz force within the Rayleigh approximation combined with anisotropic Green's functions and calculate the trapping potential of nonconservative forces using the Helmholtz-Hodge decomposition method. Tailored anisotropic and hyperbolic metasurfaces, commonly implemented by nanostructuring thin metallic layers, enables using low-intensity laser sources operating in the visible or the IR to trap and manipulate particles at the nanoscale, and may enable a wide range of applications in bioengineering, physics, and chemistry.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84338529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Bourhill, N. Carvalho, M. Goryachev, S. Galliou, M. Tobar
We demonstrate the generation of coherent phonons in a quartz Bulk Acoustic Wave (BAW) resonator through the photoelastic properties of the crystal, via the coupling to a microwave cavity enhanced by a photonic lambda scheme. This is achieved by imbedding a single crystal BAW resonator between the post and the adjacent wall of a microwave reentrant cavity resonator. This 3D photonic lumped LC resonator at the same time acts as the electrodes of a BAW phonon resonator, and allows the direct readout of coherent phonons via the linear piezoelectric response of the quartz. A microwave pump, $omega_p$ is tuned to the cavity resonance $omega_0$, while a probe frequency, $omega_{probe}$, is detuned and varied around the red and blue detuned values with respect to the BAW phonon frequency, $Omega_m$. The pump and probe power dependence of the generated phonons unequivocally determines the process to be electrostrictive, with the phonons produced at the difference frequency between pump and probe, with no back action effects involved. Thus, the phonons are created without threshold and can be considered analogous to a Coherent Population Trapped (CPT) maser scheme.
{"title":"Generation of Coherent Phonons via a Cavity Enhanced Photonic Lambda Scheme.","authors":"J. Bourhill, N. Carvalho, M. Goryachev, S. Galliou, M. Tobar","doi":"10.1063/5.0023547","DOIUrl":"https://doi.org/10.1063/5.0023547","url":null,"abstract":"We demonstrate the generation of coherent phonons in a quartz Bulk Acoustic Wave (BAW) resonator through the photoelastic properties of the crystal, via the coupling to a microwave cavity enhanced by a photonic lambda scheme. This is achieved by imbedding a single crystal BAW resonator between the post and the adjacent wall of a microwave reentrant cavity resonator. This 3D photonic lumped LC resonator at the same time acts as the electrodes of a BAW phonon resonator, and allows the direct readout of coherent phonons via the linear piezoelectric response of the quartz. A microwave pump, $omega_p$ is tuned to the cavity resonance $omega_0$, while a probe frequency, $omega_{probe}$, is detuned and varied around the red and blue detuned values with respect to the BAW phonon frequency, $Omega_m$. The pump and probe power dependence of the generated phonons unequivocally determines the process to be electrostrictive, with the phonons produced at the difference frequency between pump and probe, with no back action effects involved. Thus, the phonons are created without threshold and can be considered analogous to a Coherent Population Trapped (CPT) maser scheme.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78949711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present experimental evidence for the simultaneous existence of the magnons and spin-state transition contributions to the heat capacity in ferromagnetic (FM) Cr-doped MnTe (Tc~280K), where the magnon heat capacity is attributed to the observed magnon-bipolar carrier-drag thermopower. The pristine antiferromagnetic (AFM) MnTe shows only a magnon-induced peak in the heat capacity near the Neel temperature, TN~307K. However, Cr-doped MnTe shows a magnon-contributed heat capacity peak at ~293K with an additional peak in the deep paramagnetic domain near 780K. Temperature-dependent magnetic susceptibility reveals that Cr-doping initially creates low-spin (LS) states Mn2+ ions into MnTe near and below TN due to a higher crystal field induced by Cr ions. Above 400K, LS Mn2+ ions start converting into high-spin (HS) Mn2+ ions. The LS-to-HS transition of Mn2+ leads to an excess entropy and hence excess heat capacity contribution in the system. Temperature-dependent X-ray diffraction (XRD) and magnetic field-dependent susceptibility (M-H) confirmed no presence of any structural changes and magnetic polaron, respectively. Both XRD and M-H ensure that the peak of the heat capacity in the paramagnetic domain is originated solely by the spin-state transition. The heat capacity versus temperature was calculated to explain the contribution of each component, including the ones due to the phonons, magnons, spin-transition, Schottky anomaly, and lattice dilation. With the recent advances in spin-caloritronics extending the spin-based effects from magnetic to paramagnetic materials, the data from the heat capacity can play a crucial role to probe the presence of different phenomena such as paramagnon-carrier-drag and spin-entropy thermopowers.
{"title":"Magnon and spin transition contribution in heat capacity of ferromagnetic Cr-doped MnTe: Experimental evidence for a paramagnetic spin-caloritronic effect","authors":"M. H. Polash, M. Rasoulianboroujeni, D. Vashaee","doi":"10.1063/5.0011887","DOIUrl":"https://doi.org/10.1063/5.0011887","url":null,"abstract":"We present experimental evidence for the simultaneous existence of the magnons and spin-state transition contributions to the heat capacity in ferromagnetic (FM) Cr-doped MnTe (Tc~280K), where the magnon heat capacity is attributed to the observed magnon-bipolar carrier-drag thermopower. The pristine antiferromagnetic (AFM) MnTe shows only a magnon-induced peak in the heat capacity near the Neel temperature, TN~307K. However, Cr-doped MnTe shows a magnon-contributed heat capacity peak at ~293K with an additional peak in the deep paramagnetic domain near 780K. Temperature-dependent magnetic susceptibility reveals that Cr-doping initially creates low-spin (LS) states Mn2+ ions into MnTe near and below TN due to a higher crystal field induced by Cr ions. Above 400K, LS Mn2+ ions start converting into high-spin (HS) Mn2+ ions. The LS-to-HS transition of Mn2+ leads to an excess entropy and hence excess heat capacity contribution in the system. Temperature-dependent X-ray diffraction (XRD) and magnetic field-dependent susceptibility (M-H) confirmed no presence of any structural changes and magnetic polaron, respectively. Both XRD and M-H ensure that the peak of the heat capacity in the paramagnetic domain is originated solely by the spin-state transition. The heat capacity versus temperature was calculated to explain the contribution of each component, including the ones due to the phonons, magnons, spin-transition, Schottky anomaly, and lattice dilation. With the recent advances in spin-caloritronics extending the spin-based effects from magnetic to paramagnetic materials, the data from the heat capacity can play a crucial role to probe the presence of different phenomena such as paramagnon-carrier-drag and spin-entropy thermopowers.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81065691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seeds have been packed in a dielectric barrier device where cold atmospheric plasma has been generated to improve their germinative properties. A special attention has been paid on understanding the resulting plasma electrical properties through an equivalent electrical model whose experimental validity has been demonstrated here. In this model, the interelectrode gap is subdivided into 4 types of elementary domains, according to whether they contain electric charges (or not) and according to their type of medium (gas, seed or insulator). The model enables to study the influence of seeds on the plasma electrical properties by measuring and deducing several parameters (charge per filament, gas capacitance, plasma power, ...) either in no-bed configuration (i.e. no seed in the reactor) or in packed-bed configuration (seeds in the reactor). In that second case, we have investigated how seeds can influence the plasma electrical parameters considering six specimens of seeds (beans, radishes, corianders, lentils, sunflowers and corns). The influence of molecular oxygen (0-100 sccm) mixed with a continuous flow rate of helium (2 slm) is also investigated, especially through filaments breakdown voltages, charge per filament and plasma power. It is demonstrated that such bed-packing drives to an increase in the gas capacitance, to a decrease in the beta-parameter and to variations of the filaments' breakdown voltages in a seed-dependent manner. Finally, we show how the equivalent electrical model can be used to assess the total volume of the contact points, the capacitance of the seeds in the packed-bed configuration and we demonstrate that germinative effects can be induced by plasma on four of the six agronomical specimens.
{"title":"Seed-packed dielectric barrier device for plasma agriculture: Understanding its electrical properties through an equivalent electrical model","authors":"F. Judée, T. Dufour","doi":"10.1063/1.5139889","DOIUrl":"https://doi.org/10.1063/1.5139889","url":null,"abstract":"Seeds have been packed in a dielectric barrier device where cold atmospheric plasma has been generated to improve their germinative properties. A special attention has been paid on understanding the resulting plasma electrical properties through an equivalent electrical model whose experimental validity has been demonstrated here. In this model, the interelectrode gap is subdivided into 4 types of elementary domains, according to whether they contain electric charges (or not) and according to their type of medium (gas, seed or insulator). The model enables to study the influence of seeds on the plasma electrical properties by measuring and deducing several parameters (charge per filament, gas capacitance, plasma power, ...) either in no-bed configuration (i.e. no seed in the reactor) or in packed-bed configuration (seeds in the reactor). In that second case, we have investigated how seeds can influence the plasma electrical parameters considering six specimens of seeds (beans, radishes, corianders, lentils, sunflowers and corns). The influence of molecular oxygen (0-100 sccm) mixed with a continuous flow rate of helium (2 slm) is also investigated, especially through filaments breakdown voltages, charge per filament and plasma power. It is demonstrated that such bed-packing drives to an increase in the gas capacitance, to a decrease in the beta-parameter and to variations of the filaments' breakdown voltages in a seed-dependent manner. Finally, we show how the equivalent electrical model can be used to assess the total volume of the contact points, the capacitance of the seeds in the packed-bed configuration and we demonstrate that germinative effects can be induced by plasma on four of the six agronomical specimens.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87291493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The possibility of night-time power generation has recently stimulated interest in using the radiative sky cooling mechanism with thermoelectric generators (TEG). These passive, low-temperature difference devices have been shown to generate electricity at night with no active input of heat needed, instead using the ambient air itself as the heat source. Here, we optimize both the geometry and operating conditions of radiative cooling driven thermoelectric (RC-TE) generators. We determine the optimal operating conditions, including maximum power point and maximum efficiency point, by developing a combined thermal and electrical model. Our results show that the optimal operating condition results in larger power output than was previously expected. Moreover, we show that maximum power density occurs when the area ratio between cooler and P or N element reaches an optimal value. Finally, we perform a parametric study that takes account of environmental and structural parameters to improve the performance of the RC-TE device, including enhancing heat transfer between the hot surface and ambient air, suppressing the cooling loss of the radiative cooler, and optimizing the geometry of individual thermocouples. Our work identifies how to maximize the output of RC-TE devices and provides comprehensive guidance on making use of this new passive power generation method.
{"title":"Modeling and optimization of radiative cooling based thermoelectric generators","authors":"Bin Zhao, G. Pei, A. Raman","doi":"10.1063/5.0022667","DOIUrl":"https://doi.org/10.1063/5.0022667","url":null,"abstract":"The possibility of night-time power generation has recently stimulated interest in using the radiative sky cooling mechanism with thermoelectric generators (TEG). These passive, low-temperature difference devices have been shown to generate electricity at night with no active input of heat needed, instead using the ambient air itself as the heat source. Here, we optimize both the geometry and operating conditions of radiative cooling driven thermoelectric (RC-TE) generators. We determine the optimal operating conditions, including maximum power point and maximum efficiency point, by developing a combined thermal and electrical model. Our results show that the optimal operating condition results in larger power output than was previously expected. Moreover, we show that maximum power density occurs when the area ratio between cooler and P or N element reaches an optimal value. Finally, we perform a parametric study that takes account of environmental and structural parameters to improve the performance of the RC-TE device, including enhancing heat transfer between the hot surface and ambient air, suppressing the cooling loss of the radiative cooler, and optimizing the geometry of individual thermocouples. Our work identifies how to maximize the output of RC-TE devices and provides comprehensive guidance on making use of this new passive power generation method.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90393674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A complex experiment was performed to unravel the simplest particle,Higgs Boson, and we performed a simple experiment to address a complex system. We tested the pH response of liquid metal EGaInSn in the form of a pendant drop and measured the sensitivity of 92.96 this http URL-1 in the pH range from 4 to 10. We derived a unified Nernst equation to explain high pH sensitivity and coincidentally rediscovered Marcel Pourbaix illuminating work on the pH-Potential Diagram. The surface potential in the sensor probe is originated from a spontaneous electrochemical reaction purely driven by thermodynamics, rendering to the lowest system energy possible. Our findings have a great scientific significance, which could redefine the conventional concept of the ion sensing mechanism in a solid-state electrochemical sensor.
为了解开最简单的粒子希格斯玻色子，我们进行了一个复杂的实验，我们也进行了一个简单的实验来研究一个复杂的系统。我们测试了液态金属EGaInSn在悬垂液滴形式下的pH响应，在pH值4 ~ 10范围内测得灵敏度为92.96 this http URL-1。我们推导了一个统一的能斯特方程来解释高pH值敏感性，并巧合地重新发现了Marcel Pourbaix在pH-电位图上的启发性工作。传感器探头中的表面电位源于纯粹由热力学驱动的自发电化学反应，使系统能量尽可能低。我们的发现具有重要的科学意义，可以重新定义固态电化学传感器中离子传感机制的传统概念。
{"title":"pH-Sensitive Ultra-Thin Oxide-Liquid Metal System: A New Concept of the Fundamental Thermodynamic Limit of pH Sensitivity","authors":"A. Das, Hong Tao Wang","doi":"10.2139/ssrn.3708520","DOIUrl":"https://doi.org/10.2139/ssrn.3708520","url":null,"abstract":"A complex experiment was performed to unravel the simplest particle,Higgs Boson, and we performed a simple experiment to address a complex system. We tested the pH response of liquid metal EGaInSn in the form of a pendant drop and measured the sensitivity of 92.96 this http URL-1 in the pH range from 4 to 10. We derived a unified Nernst equation to explain high pH sensitivity and coincidentally rediscovered Marcel Pourbaix illuminating work on the pH-Potential Diagram. The surface potential in the sensor probe is originated from a spontaneous electrochemical reaction purely driven by thermodynamics, rendering to the lowest system energy possible. Our findings have a great scientific significance, which could redefine the conventional concept of the ion sensing mechanism in a solid-state electrochemical sensor.","PeriodicalId":8423,"journal":{"name":"arXiv: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81826955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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