Two-phonon infrared spectra of Si and Ge: Calculating and assigning features

Shirley, Eric L.; Lawler, Hadley M.

doi:10.1103/physrevb.76.054116

Cited by 14 publications

(7 citation statements)

References 47 publications

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“…(a) and are significant below 100 K and dominant below 50 K. The value of the loss tangent measured at the large field of 5 × 10 4 G apparently have thus quenched the loss component from electron paramagnetic resonance and our results do not give additional insight into the mechanism of this component of loss. Earlier researchers have concluded that losses arise from mechanisms such as free carrier and polaron absorption, anharmonic‐phonon absorption, and precession of electric dipoles in polar molecules . The peak observed in the loss tangent at ~100 K in some of the samples appears to be similar to that typically attributed to polaron conduction …”

Section: Resultsmentioning

confidence: 59%

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Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures

2015

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Microwave resonator measurements were performed on high‐performance microwave ceramics Ba(Zn1/3Ta2/3)O3 (BZT) and Ba(Zn1/3Nb2/3)O3 (BZN) containing additives commonly used by commercial manufacturers (i.e., Co, Mn, and Ni). We find that the loss tangent, even in ambient magnetic fields, is dominated by electron paramagnetic resonance (EPR) absorption by exchange‐coupled 3d electrons in transition metal clusters at cryogenic temperatures. The large orbital angular momentum in Co2+ and Ni2+ ions of L = 3 causes strong anisotropic‐broadened dipolar interactions that extend EPR losses to zero applied field. This effect is greatest in BZN with Co concentrations greater than 0.5 mol%, dominating the losses at liquid nitrogen temperatures (77 K) and below. In samples containing Mn2+ ions with L = 0, the dipolar interactions and associated EPR losses in ambient fields are smaller. We show the magnetic‐field‐dependent changes in the EPR losses (i.e., tan δ) and magnetic reactive response (i.e., μr) are from the same mechanism, as they follow the Kramers–Kronig relation. Finally, we note that these materials can make ultra‐high Q passive microwave devices with externally controlled transfer functions, as the quality factor (Q) of the composition Ba(Co1/15Zn4/15Nb2/3)O3 at 77 K can be tuned from 1 100 to 12 000 at 10 GHz by applying practical magnetic fields.

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Section: Resultsmentioning

confidence: 59%

“…To date, researchers have identified a number of mechanisms that can cause microwave loss in dielectrics, including free carrier and polaron absorption, EPR, anharmonic‐phonons, and precession of electric dipoles in polar molecules …”

Section: Introductionmentioning

confidence: 99%

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures

2015

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“…ELF in phonon regime Si 6K data from [88] 6K calculation from [90] Ge 2K data from [89] 6K calculation from [90] GaAs 10K calculation of [79], combined with [80] Al2O3 Analytic model, using data from [87,91] α−SiO2 Analytic model, using 300K data from [81] GaN Analytic model, using 300K data from [92] ZnS Analytic model, using 300K data from [93] SiC Analytic model of [83], with data from [94] TABLE I. Sources of the ELF in the phonon regime, for different materials.…”

Section: Methodsmentioning

confidence: 99%

“…We show the result of optical measurements at 6K for Si [88] and at 2K for Ge [89]. The dotted lines show the result of DFT calculations done assuming a temperature of 6K [90].…”

Section: Im[-1/ (ω)]mentioning

confidence: 99%

DarkELF: A python package for dark matter scattering in dielectric targets

Knapen,

Kozaczuk,

Lin

2021

Preprint

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We present a python package to calculate interaction rates of light dark matter in dielectric materials, including screening effects. The full response of the material is parametrized in the terms of the energy loss function (ELF) of material, which DarkELF converts into differential scattering rates for both direct dark matter electron scattering and through the Migdal effect. In addition, DarkELF can calculate the rate to produce phonons from sub-MeV dark matter scattering via the dark photon mediator, as well as the absorption rate for dark matter comprised of dark photons. The package includes precomputed ELFs for Al, Al2O3, GaAs, GaN, Ge, Si, SiO2, and ZnS, and allows the user to easily add their own ELF extractions for arbitrary materials.

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“…Figure 2 shows the transmittance of the retarder between 20 -250 cm −1 , measured at room temperature. Above ∼100 cm −1 the two-phonon absorption in silicon [23] reduces significantly the system's overall transmittance.…”

Section: Retarder Performancementioning

confidence: 99%

A broadband silicon quarter-wave retarder for far-infrared spectroscopic circular dichroism

Smith

Stanislavchuk

et al. 2014

Infrared Physics & Technology

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h i g h l i g h t sWe describe the design of a silicon quarter retarder working in the far infrared. The device produces far-infrared light with a high degree of circular polarization. We demonstrate its performance by photo-induced magnetospectroscopy of GaAs. 1 4 wave retarder Circularly polarized light Circular dichroism Far-infrared magnetospectroscopy Cyclotron resonance Excitons a b s t r a c tThe high brightness, broad spectral coverage and pulsed characteristics of infrared synchrotron radiation enable time-resolved spectroscopy under throughput-limited optical systems, as can occur with the highfield magnet cryostat systems used to study electron dynamics and cyclotron resonance by far-infrared techniques. A natural extension for magnetospectroscopy is to sense circular dichroism, i.e. the difference in a material's optical response for left and right circularly polarized light. A key component for spectroscopic circular dichroism is an achromatic 1 4 wave retarder functioning over the spectral range of interest. We report here the development of an in-line retarder using total internal reflection in high-resistivity silicon. We demonstrate its performance by distinguishing electronic excitations of differing handedness for GaAs in a magnetic field. This 1 4 wave retarder is expected to be useful for far-infrared spectroscopy of circular dichroism in many materials.

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Two-phonon infrared spectra of Si and Ge: Calculating and assigning features

Cited by 14 publications

References 47 publications

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures

DarkELF: A python package for dark matter scattering in dielectric targets

A broadband silicon quarter-wave retarder for far-infrared spectroscopic circular dichroism

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Two-phonon infrared spectra of Si and Ge: Calculating and assigning features

Cited by 14 publications

References 47 publications

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn1/3Ta2/3)O3 and Ba(Zn1/3Nb2/3)O3 at Cryogenic Temperatures

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn1/3Ta2/3)O3 and Ba(Zn1/3Nb2/3)O3 at Cryogenic Temperatures

DarkELF: A python package for dark matter scattering in dielectric targets

A broadband silicon quarter-wave retarder for far-infrared spectroscopic circular dichroism

Contact Info

Product

Resources

About

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures

Main Source of Microwave Loss in Transition‐Metal‐Doped Ba(Zn_1/3Ta_2/3)O₃ and Ba(Zn_1/3Nb_2/3)O₃ at Cryogenic Temperatures