Pressure and temperature dependence of the Raman phonons in isotopic γ-CuI

Serrano, Joaquim Rigola; Cardona, M.; Ritter, T. M.; Weinstein, B. A.; Rubio, Ángel; Lin, C. T.

doi:10.1103/physrevb.66.245202

Cited by 60 publications

(47 citation statements)

References 44 publications

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“…Raman measurements above 100 K on ZnO, CuI, and NaNO 3 (34)(35)(36) give Ѩln(FWHM)/ѨP near 0, whereas low-temperature slopes are larger: 1.3%/GPa for SiC; Ϸ5%/GPa for CuI, LaF 3 , and Ge; and Ϸ12%/GPa for Si and the LO mode of ZnS that is affected by a resonance (37)(38)(39)(40). The correlation of Ѩln(FWHM)/ѨP with T could be due to the methanolethanol medium being stiffer at lower T. In this case, large slopes are probably not intrinsic, and Ѩln(FWHM)/ѨP should be small compared with the compression term.…”

Section: Models Of Vibrational Heat Transportmentioning

confidence: 99%

Pressure dependence of thermal transport properties

Hofmeister¹

2007

Proc. Natl. Acad. Sci. U.S.A.

123

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Pressure (P) derivatives of thermal conductivity (k) and thermal diffusivity (D) are important to geophysics but are difficult to measure accurately because minerals, being hard and partially transparent, likely incur systematic errors through thermal losses at interfaces and spurious radiative transfer. To evaluate accuracy, repeat experiments for olivine [(Mg0.9Fe0.1)2SiO4], quartz (SiO2), and NaCl are examined in detail: these and other data on electrical insulators are compared with theory. At ambient conditions, D is underestimated in proportion to the number of contacts. As temperature (T) increases, spurious radiative transfer more than offsets contact loss. Compression of pore space and contact losses affect pressure derivatives, but these seem independent of T. Accurate (؎2%) values of D(T) at 1 atm are obtained with the contact-free, laser-flash method. Other optical techniques do not pinpoint D but provide useful pressure derivatives. Published data on ٢(lnk)/٢P at ambient conditions agree roughly with all available models, the simplest of which predicts ٢(lnk)/٢P ϳ ٢(lnKT)/٢P, where KT is the bulk modulus. However, derivatives verified by multiple measurements are reproduced accurately only by the damped harmonic oscillator model. An improved database is needed to refine this model and to confidently extrapolate these difficult measurements to geophysically relevant conditions. laser-flash analysis ͉ thermal conductivity T hermal transport properties play a crucial role in mantle convection, because this phenomenon results from competition between diffusion of heat, resistance to motion, and buoyancy forces. Thermal conductivity (k) and its relative thermal diffusivity,where is density and C P is heat capacity at constant pressure (P), are regulated by two different mechanisms. Transport of heat by phonons is termed lattice conductivity (k lat ). For electrical insulators such as mantle minerals, photons also move heat. Radiative transfer inside Earth proceeds by diffusion among the grains and is calculated from spectroscopic measurements (e.g., ref. 1). In contrast, laboratory experiments involve direct (also called boundaryto-boundary) radiative transfer wherein photons emitted from heater warm the thermocouple with minimal participation of the sample, because most electrical insulators are transparent at certain frequencies (1-3). This effect is not easily separated from k lat . Recent advances made in measurement of D using the contact-free, laser-flash technique (4, 5) allow removal of unwanted direct radiative transfer effects from the raw data. Their approach was recently applied to Earth materials at T but not at P (6-9). Pressure studies of k lat (or D) predominately involve conventional, contact methods (e.g., refs. 10-12), which potentially include simultaneous but opposing errors due to direct radiative transfer and contact resistance at interfaces (e.g., refs. 13 and 14). This report uses laser-flash results and the existing database to decipher meaningful values of Ѩk lat /ѨP. Single cr...

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Section: Models Of Vibrational Heat Transportmentioning

confidence: 99%

Pressure dependence of thermal transport properties

Hofmeister¹

2007

Proc. Natl. Acad. Sci. U.S.A.

123

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“…(ii) On the contrary, the decay probability into sum modes decreases dramatically with pressure, due to the softening of the Raman modes. The contribution to the Raman linewidth of these decay channels can be calculated using the following expressions [17]:…”

Section: Introductionmentioning

confidence: 99%

Lattice dynamics of antimony at high pressure: anab initiostudy

Serrano

Romero

2008

High Pressure Research

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“…The Raman spectra of various amorphous or crystalline materials show changes in line position and bandwidth with temperature [1][2][3][4]. This changes manifest in shift of line position and a change in line width and intensity.…”

Section: Introductionmentioning

confidence: 99%

Anharmonicity Effects in Nanocrystals Studied by Raman Scattering Spectroscopy

Dohčević‐Mitrović

Popović²,

Šćepanović³

2009

Acta Phys. Pol. A

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Phonon-phonon interactions were investigated in various nanocrystalline powders like anatase TiO 2−δ , pure CeO 2−δ and ceria doped with Nd(Gd) analyzing temperature dependent Raman spectra of these systems. Phonon confinement model based on size, inhomogeneous strain and anharmonic effects was used to properly describe the evident changes present in the Raman spectra of pure and doped ceria nanocrystalline samples. In small particles of pure and doped ceria nanocrystals, when size effects have minor impact on Raman modes, four phonon anharmonic processes prevail under the three-phonon ones. When nanopowdered particles are grown enough size effects provoke changes of the anharmonic interactions when three-phonon coupling prevails over the four-phonon anharmonic processes. In nanocrystalline anatase TiO 2 evident blueshift of the most prominent E g Raman mode probably originates from dominant four-phonon anharmonic interactions.

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Pressure and temperature dependence of the Raman phonons in isotopic γ-CuI

Cited by 60 publications

References 44 publications

Pressure dependence of thermal transport properties

Pressure dependence of thermal transport properties

Lattice dynamics of antimony at high pressure: anab initiostudy

Anharmonicity Effects in Nanocrystals Studied by Raman Scattering Spectroscopy

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